TWI306476B - A steel having excellent cuittability - Google Patents

Description

1306476 玖 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 技术 技术 技术 技术 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Steel with excellent machinability such as cutting chip treatment. BACKGROUND OF THE INVENTION Generally, a machine or an automobile system is manufactured by combining a plurality of parts, and if such parts are manufactured from a viewpoint of required precision and manufacturing efficiency, they are mostly manufactured by a cutting process, and it is required to reduce cost and improve production efficiency, and steel. It is also required to improve the machinability. The SUM23 or SUM24L, which is called low carbon fast-cut steel, is a developer who emphasizes machinability when the amount of C added is less than 0.2%. In the past, in order to improve the machinability, it is known to add a machinability improving element such as S or Pb. However, in recent years, Pb has an environmental load and tends to be avoided, and the use thereof is reduced. In the past, when Pb was not added, a method of forming a soft inclusion such as MnS in a cutting environment to improve the machinability was used. However, it was added to the low carbon SUM24L and low carbon sulfur. Quickly cut steel SUM23 equivalent S. Therefore, in order to improve the machinability, it is necessary to add more s than ever before. However, if s is added in a large amount, only the MnS is coarsened, and the effective MnS distribution cannot be formed in terms of improving machinability, and not only Calendering, forging, etc. are often the starting point of damage and cause problems such as rolling entanglement. In addition, in the case of sulfur-cut steel with SUM23 as a base material, the blade edge is likely to adhere, and the surface of the cutting surface is uneven and the surface roughness is deteriorated as the blade edge is separated and the cutting debris is separated. Therefore, from the viewpoint of the machinable I·sheng, there is a problem that the accuracy of the surface roughness is lowered. It is preferable that the cutting property is easily divided into short cuttings. However, if only s is added, since the matrix has a large ductility, it is not sufficiently divided and cannot be greatly improved. In addition to S, it is known that Te, m, p, and the like are also elements for improving machinability. However, even if a certain degree of machinability can be improved, it is preferable to minimize the occurrence of cracking due to rolling 10 or hot-rolling forging. Moreover, if it is a steel containing 0.2% or more of c, it contains a large amount of alloy halogen such as c, cr, or Mo and has high strength. In the case of such a steel for construction, since the problem of unevenness (thickness) of the cutting surface due to the formation of the blade is small and the material is originally hard, the surface roughness is good. 15 However, due to the high basic strength, if the S' of the machinability improving element is added in a large amount, the mechanical properties are anisotropic due to the stretching of the generated MnS during calendering or forging, so the application on the part is subject to Significant restrictions. Further, if the s strength steel is not added to improve the machinability, the machinability is almost lost. 20 [明内^§1] Disclosure of the Invention In view of the foregoing, the subject of the present invention is to provide a so-called low carbon steel which avoids problems of calendering or forging and product properties and which has a C content of less than 〇15%. A tool with improved tool life and surface roughness, which is excellent in 1306476, can be used as a structural steel and high-strength steel containing 0.15% or more of C. Anisotropic) and machinability of steel. The cutting system separates the destruction phenomenon of the cutting debris and promotes the cutting system. However, as described above, if the amount of S is simply increased, there is a limit. Therefore, the inventors have repeatedly studied the results of the intensive research and found that by not only increasing the amount of S but also containing Zn as a basic component, the matrix can be embrittled and broken, the tool life can be prolonged, and the unevenness of the cutting surface can be suppressed. The present invention has been completed based on the foregoing findings, and the gist thereof is as follows. 10 (1) A steel excellent in machinability, including C: 0.001 to 1.5%, Si: 3% or less, Μη: 0.01 to 3%, P: 0.001 to 0.2%, S: 0.0001 to 1.2, depending on the mass%. %, Zn: 0.001 to 0.5%, N: 0.0001 to 0.02%, Ο: 0.0005 to 0.05%. (2) The steel having excellent machinability as in the above item (1) contains Sn: 0.002 to 0.5% in terms of mass%. (3) The steel having excellent machinability as in the above item (1) or (2) further contains B: 0.0005 to 0.05% by mass%. (4) The steel having excellent machinability according to any one of the above items (1) to (3) further includes, by mass%: Cr: 0.01 to 7%, M: 0.01 to 3%, 20 V : 0.01 to 3%, Nb: 0.001 to 0.2%, Ti: 0.001 to 0.5%, and W: 0.01 to 3%, or two or more. (5) The steel having excellent machinability according to any one of the above items (1) to (4) further includes one of Ni: 0.05 to 7% and Cu: 0.02 to 3% by mass%. Or two or more types, and when it contains 0.3% or more of Cu, it satisfies Ni 1306476 % 2Cu%. (6) The steel having excellent machinability according to any one of the above items (1) to (5) further includes, by mass%: Α1:0·001~2%, Ca:.0.0002~0·01 %, Zr: 0.0003 to 0.5%, Mg: 0.0002 to 0.02% of one or two or more. (7) The steel having excellent machinability according to any one of the above items (1) to (6), further comprising: Te: 0.001 to 0.5%, Pb · 0.01 to 0.7%, depending on the mass °/«, Bi: one or two or more of 0.01 to 0.7%. BRIEF DESCRIPTION OF THE DRAWINGS 10 Fig. 1 shows a schematic diagram of a straight-cutting test. Figure 1(a) shows the straight-through cutting test method, and Figure 1(b) shows the tool movement. Fig. 2 is a view showing a small-field rotary bending test piece having a notched portion. Fig. 3 is a schematic view showing the conditions of carbon immersion, Fig. 3(a) shows a mode diagram of carbon immersion 15 quenching, and Fig. 3(b) shows a pattern diagram of conditions of normalizing. [Embodiment 3] BEST MODE FOR CARRYING OUT THE INVENTION The basic idea of the present invention is to improve the machinability by imparting Zn in addition to S, which does not impair mechanical properties. 20 That is, Zn is an especially important element in the present invention. The Zn system has an effect of embrittlement of steel and has an effect of improving machinability, and particularly has an effect of improving the thickness of the cutting surface. Further, since the conventional inclusions such as MnS are not present in the form of the coarse inclusions, the deterioration of the mechanical properties can be suppressed to a minimum, and the effect is particularly remarkable with the anisotropy 1306476. On the other hand, even if it has the same degree of mechanical properties, good machinability can be obtained when Zn is added, and it is considered that this is because the embrittlement effect of Zn is remarkable when the temperature rises due to the heat of cutting. Furthermore, it is generally considered that a full slip effect is produced on the tool/cut # interface during cutting. If & less than 5 0.001%, the effect is small. On the other hand, since Zn is not easily vaporized during the dissolution, in order to keep Zn in the molten steel and maintain a mass of more than 〇5% after solidification, it is necessary to use a large amount of Zn, but from the cost of green. From the point of view, it cannot be achieved industrially, so the upper limit is 〇5%. Therefore, the range of Zn content of this steel is limited to o.ooi~0 5%. In addition to Zn, it is also possible to carry out a step-cutting enhancement element such as Sn, B, Te, etc. However, if Sn is added alone, the machinability cannot be improved, and the two are enhanced by the interaction with Zn. Machinability. The reason for limiting the steel composition other than Zn is explained below. C : 0.001 to 1.5% 15 Since C is related to the basic strength of steel and the oxygen content in steel, u has a great influence on the machinability. If a large amount of c is added to increase, +A is 8%, which lowers the machinability. Therefore, the upper limit is 1.5%. On the other hand, in order to prevent the formation of a hard oxide which reduces the machinability and to suppress the disadvantage of solid solution oxygen at a high temperature such as pinholes in the solidification process, it is necessary to suppress the oxygen content in an appropriate amount. If it is excessively reduced by the blowing (the amount is not increased, the amount of oxygen in the steel remains large and the pinhole is caused by a large amount of oxygen in the steel. Therefore, problems such as pinholes can be easily prevented (: The amount of 〇〇〇1% is lower yang, Si: 3% or less, etc. will become trapped. Adding Si will reduce the hot rolling ductility and the pressure is 20 1306476. If it is added moderately, it will impart mechanical properties or soften the oxide. And the machinability is improved, and the upper limit is 3%. If it is more than 3%, the hot rolling ductility is lowered to make rolling and the like difficult, and industrial production is difficult. Further, it is also possible to produce a hard oxide and reduce the machinability. 5 Mn: 0.01 to 3.0% Μ η is a deoxidizing element, and #MnS is necessary for fixing and dispersing sulfur in the steel, and is necessary for softening the oxide in the steel and making the oxide harmless. 'Although the effect is related to the amount of S added, if it is less than Q.Q1%, the added S cannot be sufficiently fixed by MnS, and S becomes FeS and becomes brittle. If 10 increases the amount of Μη, the hardness due to texture Will become large and the machinability or cold rolling processability will be reduced, so The upper limit is 3.0%. Ρ : 0.001 ～0.2% Since the hardness of the steel in the steel is increased, and not only the cold rolling processability, but also the hot rolling processability or casting characteristics are lowered, the upper limit must be 0.2 15 %. On the other hand, by embrittlement, it is easy to cut and is effective in improving machinability, and the lower limit is 0.001%. S : 0.0001 ～1.2% S system is combined with Μη MnS inclusions exist. Although MnS can improve the machinability, the stretched MnS is the cause of the anisotropy during forging. The coarser ^^1^ should be avoided, but the machinability can be improved. From the viewpoint of the above, it is preferable to add a large amount of 'VtnS finely dispersed. In order to improve the machinability, it is necessary to add 0.0001% or more, and it is preferable to add 〇〇〇1% or more. On the other hand, if it is larger than 1.2. % is not only incapable of avoiding the formation of coarse MnS, but also due to the deterioration of casting properties and hot rolling deformation characteristics due to FeS, etc., which is deteriorated during manufacturing, so 12% is the upper limit. N : 0·0001 〜〇 02% Ν is solid solution 会使 will harden the steel, especially in the cut The cutting time hardens near the blade due to the dynamic strain aging, and the tool life is reduced, but also has the effect of improving the thickness of the cutting surface. Further, it is connected with β to form ΒΝ and improve y machinability. The 剌 content is less than 〇 ._1%, since the surface roughness improvement effect by solid solution nitrogen or the machinability improvement effect by BN is not seen, 0.0001% is the lower limit. Further, if the N content is more than 〇〇2% °, In the present invention, since the amount of solid solution nitrogen is large, the life of the tool is lowered, and 10 bubbles are formed during casting, which is a cause of defects, etc., so that the above disadvantages become 0.02%, which is an upper limit. 0 : 0.0005 to 0.05% If Ο is present in a free state, it becomes a bubble and becomes a pinhole when it cools. Further, in order to soften the oxide and suppress the hard oxide which has 15 defects in machinability, it is necessary to control it. Further, when the MnS is finely dispersed, the oxide is also used as a precipitated core. When the content of ruthenium is less than 〇 〇〇〇 5%, the MnS cannot be sufficiently dispersed finely and coarse MnS is generated and adversely affects mechanical properties, so 0.0005 is the lower limit. Further, if the content of cerium is more than 0_05%, bubbles become bubbles during casting and become pinholes, so 20 is set to 0.05% or less.

Sn : 0.002~0.5%

Sri is a soft metal, which is distributed in the grain boundary in steel to embrittle the steel, thereby improving the machinability. When the amount of addition is 0.002% or less, the effect is not observed. If it is more than 0.5%, it is difficult to make the rolling and the rolling become 1306476 due to the embrittlement of the steel. Therefore, the range is set to 0.002 to 〇.5%. B : 0.0005~0.05% B can effectively improve the machinability. If the addition amount is less than 〇._5%, the effect is not significant. If the addition amount is larger than that of the surface, the effect is saturated, and if 5 excessive precipitation of BN due to thermal hysteresis, the casting property and heat deformation may occur. The deterioration of the characteristics causes cracks in the manufacturing 1 to 〇〇〇〇5~〇. (4) is its range.

Cr : 0.01 to 7%

Cr is an element that enhances hardenability and imparts tempering and softening. When it is added by a large amount of 10, it can be obtained as a property. Therefore, it is added to a steel having a high strength. In this case, it is necessary to add just above, but if a large amount is added, a & carbide is formed and embrittled. Therefore, the upper limit is 7%.

Mo : 〇.〇1 ~ 3%

Mo is an element that imparts temper softening resistance while improving hardenability. If the addition is less than 0 genus, the effect cannot be seen. If the addition amount is greater than %, then (4) the effect is saturated, so the range is added by 0.01% to 3%. V : 0.01 to 3.0% # V can form carbonitrides and strengthen the steel by secondary precipitation hardening. If the amount is less than 0.01%, the high strength does not have an effect. If the amount is more than 3%, 20 will precipitate a large amount of carbonitride and adversely affect the mechanical properties, so the upper limit is 3%.

Nb : 0.001 ~ 0.2%

Nb can also form carbonitrides and strengthen the steel by secondary precipitation hardening. If the addition amount is less than 0.001%, high strength does not have an effect. If the addition amount is more than 12!3〇6476 •"/o, a large amount of carbonitride will be precipitated and the mechanical properties will be impaired. Therefore, the upper limit is 0.2%. .

Ti: 0.001 ~ 〇.5 〇 / 0 Τ ι can also form carbonitrides and strengthen the steel ◎, also deoxidizing elements, and can improve the machinability by forming a soft oxide. If the addition amount is less than the effect, the effect cannot be seen. If the addition amount is more than 〇5%, the effect is saturated, and Ti becomes a nitride at a high temperature and suppresses the growth of the Worthite granules, so the upper limit is 0.5%. . w : 0.01 to 3%, W forms carbonitrides and strengthens the steel by secondary precipitation hardening. If the addition amount is less than Q.G1%, then the south strength does not have an effect. If the addition amount is larger than the opposite, the coarse carbonitride will be precipitated and the mechanical properties will be impaired. Therefore, the upper limit is 3%.

Ni : 〇.〇5 ~ 7%

Ni can strengthen the fat granules and increase the ductility. It is also effective in improving the susceptibility and improving the purity. If the amount of addition is small, the effect cannot be seen. If the amount is more than 7%, the effect is saturated in terms of _ properties, so the upper limit is 7%.

Cu : 0.02 to 3% 20

Cu can strengthen the sculpt ship materials, which is also effective in improving the susceptibility and improving the purity. If the amount of addition is less than 2%, the effect cannot be seen. If the amount of addition is large (4), the effect is saturated in terms of mechanical properties. Therefore, adding Cu to the right of 7 at the upper limit of 3% will result in extreme, a,, and >rj 苜 Μ Μ 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低 降低When the amount added is more than 〇.3%, in order to avoid problems in manufacturing, the addition amount of Ni is preferably added as Ni% $cu%. A1 : O.ooi~2% A1 is a deoxidizing element and forms Al2〇^tA1N in steel. This can reduce the grain size of the Worth field during quenching and improve the workability. Less than 〇.〇〇1% can not see its effect, if it is greater than strong, it will produce coarse inclusions, and will reduce the mechanical properties. Further, since Al2〇3 is hard, it causes damage to the tool during cutting, and 1 may increase the loss. Therefore, the coarsening effect of the Wolsfield granules and the like is saturated and the disadvantage of Al2〇3 is significantly limited to 2%, especially if the machinability is preferred, it is preferable to set the reading of Al2〇3 in a large amount. When the softening of the oxide is preferred, it is preferably 0.005% or less.

Ca : 0.0002~〇

Ca is a deoxidizing element and forms a soft oxide and improves machinability. Not only is Ca solid dissolved in Mns to reduce its deformation energy, but even if it is calendered or hot-rolled forged, it has the effect of suppressing the extension of the shape. Effectively reduce the anisotropic element. If the addition amount is less than 〇〇〇〇2%, the effect is not significant. If the addition amount is more than 〇〇1%, not only the yield is extremely deteriorated, but also the hard Ca 〇 is generated. In addition, CaS, etc., will reduce the machinability, and thus the composition range is specified to be 0.0002 to 0.01%.

Zr : 0.0003 ~ 〇 5%

Zr is a deoxidizing element and forms an oxide. The oxide system constitutes a precipitated nucleus of MnS and has an effect of uniformly dispersing MnS uniformly. Further, & is solid-dissolved in MnS to lower its deformation energy, and has a function of suppressing the elongation of MnS by 14 l3〇6476 even if it is calendered or hot-rolled forging, so it is an element which effectively reduces anisotropy. If the addition amount is less than 〇._3%, the effect is not significant. If the addition amount is more than 0.5%, not only the yield is extremely deteriorated, but also a large amount of hard is generated.

ZrOdZrS, etc., will reduce the machinability, so the composition range is set at 0.0003 to 0.5%.

Mg : 0.0002~0.02%

Mg is a deoxidizing element and forms an oxide. The oxide system has an effect of suppressing the anisotropy of the nucleus and has an effect of uniformly dispersing and dispersing MnS. If the addition amount is less than 〇〇_, the effect is not significant. If the addition amount is more than 0.02%, not only the yield is extremely deteriorated but the effect is saturated, so the composition range is specified in 〇〇〇〇2 to 〇〇2%. .

Te : 0.001 ~ 0_5%

Te is a machinability. Further, it has an effect of reducing or suppressing the deformation of the MnS and suppressing the extension of the MnS shape by coexistence with MnS, so that it is an element which effectively reduces anisotropy. If the amount added is less than 〇〇〇1%, the effect cannot be seen. If the amount added is greater than 〇.5%, the effect is saturated.

Pb, Bi: 0.01 ~ 0 '70 / 0

Pb and Bi are elements that effectively improve the machinability. If the addition amount is less than 0.01%, the effect cannot be seen. If the addition amount is more than 0.7%, the effect of improving the 20 machinability is not only saturated, but the hot-rolling forging property is lowered to easily cause enthalpy, so the content thereof is set separately. It is 0,01~〇7%. EXAMPLES The effects of the present invention will be described by way of examples. One part of the test material with the chemical composition shown in the table is dissolved in a 270t converter, and then decomposed and calendered into a small 15 1306476 embryo, and then rolled into a bar of φ 50mm, and the others are melted and calendered in a 2t_vacuum dissolution furnace. . The machinability of the materials shown in Examples 1 to 4 of Table 2 was evaluated by the drill bit perforation test and the cutting conditions are shown in Table 3. The machinability was evaluated by cutting to the highest cutting speed of the cumulative hole depth of 1000 mm (so-called VL 丨〇〇〇). 10

Further, the surface roughness was evaluated by a so-called straight-through (four) 复制 which duplicated the tool-shaped silver with a flat-pressure cutting tool. A summary of the experimental method is shown in the figure. That is, as shown in Fig. 1(a), the tool 2 is rotated by the tool 3 to rotate the workpiece 2' toward the cutting side, and as shown in the first (_), the surface roughness is measured by 4 to move the tool 3. The cutting conditions are shown in Table 4. The experimental system measures the thickness of the processing 2 (10-point surface roughness ΚζμΓη). In the imaginary, Nt t Ζ the cutting shoulder handling property shown in Table 2 'cutting debris system is formed as crimping The shape 'Λ A 5i& η -τ- , , has been smashed as follows and _ shards (four) and generated a short cut of more than 5 rolls but not broken (four) is called 〇 'name

16 1306476 Table 1 Examples Chemical composition (iass%) No. Distinguish C Si lin PS Zd Sn B Te Pb Bi N 0 1 Invention Example 0.009 0.007 1.540 0.071 0.502 0.0098 - - 0.0167 0.0178 2 Invention Example 0.018 0.012 1.512 0.078 0.494 0.0063 0.014 - 0.0176 0.0190 3 翻数0.008 0.008 1.090 0.090 0.530 0.0075 0.016 - 0.0099 0.0179 4 Inventive Example 0.014 0.015 1.688 0.080 0.550 0.0039 0.009 0.0020 0.0083 0.0179 5 Comparative Example 0.011 0.013 1.410 0,074 0.458 - - 0.0111 0.0165 6 Comparative Example 0.019 0.013 1.430 0.071 0.468 - 0.029 - 0.0131 0.0159 7 Turning 0.051 0.013 1.606 0.07? 0.526 0.0064 - - 0.0091 0.0173 8 Invention Example 0.024 0.004 1.429 0.077 0.467 0,1181 - - 0.0143 0.0198 9 Invention Example 0.036 0.005 1.471 0.082 0.481 0.4462 - - 0,0083 0.0201 10 Inventive Example 0.057 0.007 0.919 0.081 0.452 0.0054 Glycol 0.0030 0.0094 0.0183 11 Inventive Example 0.057 0.011 1.651 0.079 0.540 0.0058 0.013 - 0.0126 0.0191 12 Inventive Example 0.023 0.010 0.988 0.076 0.476 0.0070 0.015 - 0,0165 0.0183 13 Inventive Example 0.050 0.005 1.4 09 0.081 0.459 0.0067 0.015 0.0024 0.0126 0.0196 14 Comparative Example 0.024 0.009 1.424 0.082 0.464 - - - 0.0132 0.0150 15 Invention Example 0.076 0.010 0.983 0.074 0.322 0.0051 - - 0.0103 0.0197 16 Invention Example 0.071 0.003 0.897 0,077 0.299 0.0034 0.007 - 0,0117 0.0198 17 Inventive Example 0.073 0.003 0.909 0.077 0.300 0.004? 0.011 0.0034 0,0098 0.0200 18 Inventive Example 0.083 0.007 0.861 0.088 0.287 0.0059 - - 0.275 0.0137 0.0151 19 Inventive Example 0.072 0.004 0.907 0.071 0.297 0.0092 0.020 - 0.271 0.0143 0.0177 20 Invention Example 0.084 0.014 1.002 0.071 0.331 0.0085 0,019 0.0027 0.186 0.0142 0,0186 21 Invention Example 0.078 0.013 0·foot 0.085 0.292 0.0049 — - 0.113 0.0084 0.0199 22 Comparative Example 0.079 0.014 1.068 0.089 0.348 - - - 0.0145 0.0202 23 Comparative Example 0.080 0.003 1.065 0.075 0.347 - - - 0.279 0.0119 0.0186 24 Comparative Example 0.071 0.010 0.909 0.072 0.299 Continued - Secret 0.177 0.0178 0.0157 25 Ratio Off 0,071 0.002 0.911 0.089 0.300 - - - 0,119 0,0120 0.0208 26 Comparative Example 0,076 0.004 1.459 0.084 0.479 — 0.057 0.0099 0.0171 27 翻数0,073 0.012 1.533 0.073 0.503 0.0039 * - 0.0104 0.0197 28 Exception 0.073 0.008 1.426 0.086 0.465 0.0079 0.009 - 0.0131 0.0182 29 Invention Example 0.073 0.005 1.013 0.085 0.491 0.0070 0.017 - 0.0119 0.0200 30 Invention Example 0.079 0.007 1.589 0.072 0.521 0.0066 0.017 0.0028 0.0130 0.0194 31 Comparative Example 0.087 0.015 1.624 0.082 0.530 - - 0,0176 0.0165 32 Remuneration 0,080 0.002 2.204 0.079 0.720 0.0046 - - 0,0146 0.0152 33 Invention Example 0,079 0.011 2.188 0.082 0.712 0.0060 book - 0.0090 0.0202 34 Invention Example 0.088 0.002 2.147 0.084 0.699 0.0088 0.010 - 0,0105 0.0155 35 Invention Example 0.081 0.014 2.203 0.078 0.717 0.0035 0.019 0.0018 0.0140 0.0204 36 Comparative Example 0.077 0.003 2.056 0.077 0.672 - - - 0.0141 0.0189 37 Case 0.075 0.012 0.332 0.083 0.087 0.0043 - - 0,0142 0.0206 38 Invention Example 0.081 0.002 0.346 0. Which 0.088 0.0095 0.020 - 0.0163 0.0169 39 Remuneration 0.078 0.006 0.384 0.087 0.096 0.0056 0.012 0.0017 0.0129 0.0177 40 Comparative Example 0.0 71 0.012 0.326 0.090 0.083 - - - 0.0178 0.0174

17 1306476

Table 2 Example Evaluation No. Distinguishing VL1000 Surface Roughness Cutting Debris Handling Property 1 Inventive Example 138 11.3 〇2 Inventive Example 133 11.4 〇3 Inventive Example 138 10.2 〇4 Inventive Example 137 9.9 〇5 Comparative Example 91 19.5 〇6 Comparative Example 93 24.3 〇7 Inventive Example 133 9.3 〇8 Inventive Example 139 9.6 〇 9 Inventive Example 133 9.1 〇 10 Inventive Example 139 9.7 〇 11 Inventive Example 139 10.6 〇 12 Inventive Example 136 9.8 〇 13 Inventive Example 138 10.2 〇 14 Comparative Example 104 20.6 〇15 Inventive Example 124 11.2 〇16 Inventive Example 138 10.6 〇17 Inventive Example 136 9.5 〇18 Inventive Example 173 11.8 〇19 Inventive Example 173 10.1 〇20 Inventive Example 176 9.4 〇21 Inventive Example 137 10.4 〇22 Comparative Example 79 22.2 X 23 Comparative Example 154 9.5 〇24 Comparative Example 153 11.5 〇25 Comparative Example 97 22.2 〇26 Comparative Example 72 19.7 X 27 Inventive Example 127 11.1 〇28 Inventive Example 125 10.9 〇29 Inventive Example 131 11.0 〇30 Inventive Example 131 9.1 〇31 Comparative Example 86 23.6 〇32 invention example 138 9.4 〇 33 invention example 134 10.9 〇 34 invention example 134 11.7 〇 35 invention example 136 11.5 〇 36 ratio Comparative Example 93 21.9 〇 37 Invention Example 93 11.3 〇 38 Invention Example 92 10.9 〇 39 Invention Example 98 9.3 〇 40 Comparative Example 71 19.2 X

18 1306476 Table 3 Cutting conditions Other cutting speeds of the drill bit 10-200m/min Feed 0.33mm/rev Insoluble cutting oil φ 5mm NACHI General drill protrusion amount 65mm Hole depth 15mm Tool life loss until Table 4 Cutting condition bit _____ Other Cutting speed 80m/min Feed 0.05mm/rev Water-insoluble cutting oil equivalent SKH51 Angle 15° Angle of separation 6° Outstanding evaluation point 200 cycles Inventive example has excellent bit tool life relative to the comparative example' At the same time, the surface roughness is good in straight-cutting. This is not changed when the addition of 5, C, S, etc. is different. When adding elements such as Zn, Sn, B, etc., compared with the same C, S, etc. Steel also has excellent tool life and surface roughness. A large amount of S tends to have good machinability, but when the amount of s is small, the chipping property can be improved. On the other hand, as in Comparative Examples 6 and 26 of the examples, when Zn was not added when Sn was added, the machinability could not be improved. Further, when a moldable property-enhancing element such as Te, Pb or Bi is contained, the addition of Ζ η also exhibits superior machinability. Similarly, Table 6 shows the evaluation of the machinability and mechanical properties of the steel having the structural carbon steel as the base material of the chemical composition of the sample shown in Table 5. The ~ part of each test material is dissolved in a 270t converter, and then decomposed and calendered into small embryos, and then rolled into a bar of Φ 65mm, and the others are dissolved and calendered in a 2t-vacuum dissolution furnace. The impact value (J/cm2) was evaluated by making a U-shaped test piece having a depth of 2 mm based on jis. 19 The evaluation of the machinability of Examples 41 to 43 containing ο·1% α was shown in Table 3 for the scallops. The machinability was evaluated by cutting to the highest cutting speed (so-called VL 丨〇〇〇) of the cumulative hole depth of 1 OOO mm. 5 Further, the surface roughness was evaluated by a so-called straight cut using a flat-pressure cutting tool to duplicate the shape of the tool. The experimental system measures the surface roughness when 200 grooves are processed. The surface roughness was evaluated by the straight cut shown in Table 4. With respect to Examples 47 to 46 containing about 0.3% of c and Examples 47 to 77 which are larger than the amounts of C of Examples 44 to 46, since the mechanical properties were emphasized, the impact value and the anisotropy thereof were exhibited. Here, the impact value of the sample cut out from the cross-sectional direction of the bar steel ("C direction" block) is displayed, and the anisotropy system shows (the impact value of the sample in the cross-sectional direction) / (the impact value of the long-term sample) ( "Anisotropy" column). The larger the value, the less anisotropy is shown. Further, the machinability evaluation of Examples 47 to 77 was carried out by the drill hole piercing property 15 VL1000, and was evaluated under the cutting conditions shown in Table 7, and the thickness of the cut surface was not evaluated at this time. 20 w 0 eft Μ S w, Φ chain M o [0. 0052! 10.0088 1 i 0.0046 II 0.0026 | I 〇|0. 00151 10. 0018 | ί 0'00171 10. 0016 I 10. 0020 1 I 0. 0013 I 1 0. 0015 | 0.0013 L〇. 00201 10·0020| I 0. 0017 | 10. 0019 | [0. 0014] 10. 0016 I 0. 0020 10. 0013! φ δ ο 0. 0021 0. 0021 10.0017 10. 00151 I a 00221 0,0016 0.0022 0.0019 0.0015 0.0018 0. 0018 0.0018 0.0021 10. 0020 |〇. 0015| z 1 0.0065 1 1 d [0^)046 Ί I 0.0046 | 1 0.0045 I 1 0.0051 1 I 0.0064 10.0059" 1 0.0048 1 [0.0052 1 1 0.0050 1 I 0.0061 II did [0.0057 I | 0.005» | 1 0.0054 II O.OOS4 II 0.0064 II 0. 0052 I 3? S d 1 0.0054 1 1 0.0049 II 0. 0052 I 1 0. 0055 II o' M id 1 d § ο | 0.0059 | | 0.0064 | I 0.0047 I 1 0.0056 0.0045 M 1 d S d 1 0. 0052 | ώ 1 0.0026 1 1 0.0021 I 〇8 d 1 0.0016 II 0.0028 | I 0.0013 | I 0.0018 ] 00 id [0.0013 1 id I 0. 0022 | I 0.0011 | 5 sso* 1 0. 0022 ) ί 0. 0028 | ΙΛ id |0.0012 IB 8 6 id 00 d 8 d 1 0.026 | 1 0.032 1 1 0.029 1 i 0.018 | 1 0.035 1 1 0.018 1 1 0.030 i 1 0.0X9 1 1 0.021 ] 1 0.021 1 ο 1 0.030 | | 0,020 | I 0.024 | 1 0.034 1 1 0.017 1 I 0.029 j 1 0.0X9 I [0.035 I 1 0.023 1 1 0.029 1 1 0.017 1 1 0.0016 I ! 0.0028 1 I 0.0021 i 1 0.0016 1 1 0.0023 1 [0.0029 1 1 0· 0023 1 1 0. 0024 1 I 0. 0016 | f 0. 0014 1 1 0. 0025 1 I 0. 0026 | 1 0. 0021 1 1 0. 0021 1 1 0. 0028 I — I 0.043 I 1 0.043 1 1 0.033 1 z 1 0.037 1 1 0.024 1 1 0.024 1 > 1—0.11 1 1 0.10 I 1 0.12 I m 1 1 1 1 1 1 i 1 1 1 1 1 1 1 1 \ 1 1 1 i 1 1 1 1 1 i 0.0033Ί 1 I f 1 1 I 1 1 ί 1 t & I 1 0.0098 1 1 1 1 0.0155 1 I 1 0.0107 1 1 1 1 0.0164 1 i 1 I 1 0. 0144Ί ! ] 1 0.0093 I t 1 Male S d 1 1 This o 1 t 1 0.01691 1 1 卜2 O o' i 1 1 0.0196 | 1 1 r〇. 0115 1 1 t5 I 0. 0043 | i 0. 0050 | 1 i O 1 0.0069 1 l· 0. 0020 1 V 1 0.0050 1 1 0. 0076 1 1 0. 0100 ι 1 1 10. 0053 ! I 0. 00 67Ί 1 id 1 O 1 1 0.0091 | [0.0077 1 II 0.0035 I [0.0072 1 1 [0. 0045 1 1 0.0077 1 1 1 0.0065 1 [0.0067 1 i 1 0. 0077 1 IO i 1 0.0034 1 1 0. 0053 1 ! CO C4 s 6 丨0.016 1 1 0.025 1 00 — od 1 0.019 1 1 0.024 I f 0.029 1 〇d 1 0.018 ! [0.013 | 1 0.017 i 1 0.019 1 1 0.114 | I 0.025 1 sod E 0.022 I i ό 1 d 1 0.018 ! I 0.0X2 | 1 0.015] 1 0.024 1 1 0.025 i 1 0.022 1 Γ0.016 1 1 0.013 1 1 0.027 1 Γ 0.016 1 ! 0.020 1 “0,015 1 1 0.029 1 [0.019 1 bO B ό 1 0.029 1 1 0.087 1 1 0.117 1 1 0.082 I CL. 0.029 j 8 Ο ό i 0.024 1 1 0.023 1 1 0.013 1 1 0.013 I 1 0.029 1 [0.021 1 i 0.027 I 1 a 015 ii 0.027 ! 1 0.015 ! 1 0.014 jt 0.021 1 CQ sd I 0.029 Ί 1 0.014 I i 0.018 I f 0.015 1 f 0.015 j 1 0.018 1 \ 0.016 1 [0.021 1 I 0.016 | I 0.027 1 f 0.025 | od U) sdt 0.018 | 1 0.025 | | 0,029 1 1 0.015 | l 0.019 | \ 0.015 1 I 0.019 | j 0.027 1 [0.030 | eoi 0.56 1 1 0.51 1 O soososo [0.62 1 1 0.68 I 1 0.88 1 «VJ iO os o' l_〇,n J 1 0.67 1 1 0.76 I 00 (0 d 1 0v7i -1 Γ 0. 78 1 1 0.79 | wd 1 0.73 I LQ,80J] 丨m” doso 〇od 丨0,77 1 sou ό ogo μ ό 1 0.82 1 1 0.65 | V3 i 0.311 l 〇· 18! 1 0.33 1 [0.17-1 L 0J8 J 1 0.29 1 i 017 J s 〇 · K d Q.\s\ 〇· 1 0.24 ! d I 0.30 1 I 0.23 | I 0.28 | 1 0.19 1 1 0.30 1 d Q0 d 8 d 1 0.23 1 1 a33 1 d 1 0.19 1 λ « d Si ό Γ0Γ29 1 <0 d 1 0.22 I 1 0.25 1 L0.24 J 1 0.32 I d 1 0.20 1 1 0.24 1 1 0.21 1 uod on 1 0.10 1 0.32 1 o ! 0.31 1 I 0 43 I 10,43 J t 0 44 j | 0.54 I 10.551 i 0.57 1 丨0,4S 1 5* d I 0.44 i ss o I 0.43 | 1 0.43 II 0.43 1 1 0.44 I 1 0.46 1 f 0.43 1 1— 047 1 1 0.47 | 1 0.44 I Γ 0.43 1 \ 0.45 1 [0.43 1 i 0.44 1 !5 1 0-47 1 1 0.43 1 Γ0. 46 ] Γ 0.44 I 1 0.45 1 1 0.42 1 "X 45 s 掲l〇 l 1 Division 1 box 5 鞔I invention example 睇ui invention example | 鞔铕1 鞔u JJ U £ 1 invention example 1 Ϊ Ϊ 盔 盔 丨 丨 丨 丨 丨 丨 j j j j j j 丨 丨 丨 丨 丨 ¥ ¥ Comparative Example 1 s ene s stew 1 invention example 1 £ 翻 w overflow W grade [invention example Π f 5 9 3 5 ss to CVJ in KS Cs· in ss s 3 λ Φ s φ sg JJ | 2 21 1306476 Table 6 Example Machinability Hardness HV Impact Value No. Distinguish VL1000 Surface Thickness C Direction Anisotropy 41 Inventive Example 65 20.3 128 — — 42 Inventive Example 65 21.2 132 — - 43 Comparative Example 45 33.5 132 - 44 Inventive Example 52 - 167 53.4 0.55 45 Inventive Example 57 - 165 53.4 0.53 46 Comparative Example 43 - 174 52.1 0.55 47 Inventive Example 47 - 194 41.6 0.52 48 Inventive Example 50 - 184 38.1 0.55 49 Comparative Example 37 - 196 38.0 0.59 50 Inventive Example 44 - 206 36.2 0.45 51 Inventive Example 36 - 215 35.3 0.46 52 Comparative Example 25 - 203 35.9 0.48 53 Comparative Example 46 - 199 18.9 0.29 54 Inventive Example 45 - 210 35.4 0.44 55 Inventive Example 37 — 202 37.3 0.58 56 Comparative Example 26 — 208 36.9 0.53 57 Inventive Example 43 — 206 36.6 0.54 58 Inventive Example 44 — 212 35.9 0.51 59 Comparative Example 26 — 212 37.7 0.51 60 Inventive Example 38 — 201 37.3 0.51 61 Inventive Example 42 — 205 35.9 0.46 62 Comparative Example 25 - 202 36.4 0.51 63 Inventive Example 45 - 198 41.4 0.63 64 Inventive Example 50 - 192 39.8 0.52 65 Comparative Example 34 193 41.4 0.54 66 Inventive Example 50 - 202 41.5 0.66 67 Inventive Example 50 - 192 39.0 0.53 68 Comparative Example 35 - 196 41.2 0.54 69 Inventive Example 46 - 205 38.5 0.51 70 Inventive Example 48 A 204 40.0 0.64 71 Comparative Example 31 - 201 39.6 0.55 72 Inventive Example 48 - 206 40.4 0.59 73 Inventive Example 48 - 192 38.7 0.50 74 Comparative Example 31 - 208 38.6 0.48 75 Inventive Example 47 - 193 38.9 0.59 76 Inventive Example 48 - 205 41.2 0.52 77 Comparative Example 35 - 203 40.4 0.64 22 1306476 Table 7 Cutting conditions Other cutting speed of the drill bit 1 _200 m / min Feed 0.25 mm / rev Water-soluble cutting oil Φ 3 mm NACHI General drill bit protrusion amount 45 mm Hole depth 9 mm Tool life loss before the comparison of Examples 41 to 43, the invention example The comparison example is superior to VL1000 and surface roughness. Further, in the examples 44 to 77, it is understood that the impact value of the sample in the case of the comparative example having substantially equal C and other alloying elements in the hardness Hv, the cross-sectional direction, and the impact value of the sample in the cross-sectional direction. The (the impact value of the long-term sample) was substantially equal, but the VL1000 of the invention example was excellent and the machinability was excellent. Further, as in Comparative Example 53, when the machinability was improved by increasing the amount of S, the anisotropy of the impact value was lowered, so that the performance as the structural steel was inferior to that of the examples 47 and 48. Table 8 shows an example in which a large amount of alloying elements and a steel which improves hardenability are used as a substrate. One part of the test material was dissolved in a 270t converter, and then decomposed and calendered into small embryos, which were then rolled to φ 50mm, and others were dissolved and calendered in a 2t~ vacuum melting furnace. 15 Examples 78 to 82 are steels with SCr420 as the base material, and are subjected to normalizing (92 (TCx lhr-air cooling) and supplied to the cutting test. The machinability evaluation is performed by the drill bit perforation test and the cutting conditions and the table. 5 is the same, the evaluation item is the highest cutting speed that can be cut to a cumulative hole depth of 1000mm (so-called VL1 〇〇〇). The unit of VL1000 is m/min, and the larger the tool life is, the better the hardness is. At the same time, as shown in Fig. 2, a small-field rotating bending test piece having a notch of R1.16 mm was opened on the test piece, and the conditions shown in Figs. 3(a) and 3(b) were After the carbon immersion, the fatigue characteristics were evaluated. 23 1306476 As a result, although the hardness after normalizing as shown in Fig. 3(b) is substantially the same, the VL1000-based developed steel is superior. The fatigue characteristics after carbon immersion are substantially equal, and the present invention is known. Although the technology can improve the machinability, it will not degrade the performance of the gears.

24 1306476 oom Fatigue Limit MPa | 499 | [505 1 | 496 1 s in 485 Hardness HV 1 153 1 L 1.49 1 Lis〇 — 1 149 | Machinability VL1000 CO CO ss CO Chemical Composition (eass% > 〇10.0021 | [ 0.0059 | [0.0056 | |0.0052 1 |0.0042| as 10.00561 |〇.0050 1 10.00451 10.0056! |0.0060| *< | 0.032 | | 0.034 1 | 0. 032 | 1 0.026 | | 0.018 1 LO o | 0.94 1 Οϊ Of—4 | 0.94 | | 0.91 1 CO 1 10.00271 1 1 1 CO 1 1 |0.O163| 1 1 e5 10.00751 10.0032| 10.00781 1 1 c/> | 0.013 | | 0.017 | | 0.013 | | 0.013 I | 0.046 1 | 0.016 | | 0.018 1 | 0.014 | | 0.020 1 [0. 016 1 1 〇y71 1 | 0.70 1 | 0.72 ] | 0.79 1 1 0.71 I CO | 0.19 1 [0.19 1 | 0.19 | | 0.19 1 | o | 0.21 | L〇^2〇J | 0.18 | 1 0.21 1 0.19 Example Differentiation Invention Example Invention Example Comparative Example | Comparative Example 00 00 1306476 Table 9 shows that the alloying element is further added in a large amount and the hardenability is improved. An example of steel as a substrate. One part of the test material is dissolved in a 27-turn furnace, decomposed and calendered into small embryos, and then calendered to a medium of 5 mm. Then, it was dissolved and calendered in a vacuum bath furnace. The machinability evaluation was carried out by the drill bit 5 test and the cutting conditions were the same as in Table 7. The evaluation item was the highest cutting speed that can be cut to a cumulative hole depth of 1000 mm (so-called VL丨〇〇〇). Examples 83 to 8 8 were made of SCM440 as a base steel, and the hardness was adjusted to HV310 by quenching and tempering, and the machinability evaluation was performed by 乂1^1000. The mechanical properties were evaluated for the impact value. The impact value was measured by cutting the sample from the length of the steel bar 10 and was measured by JIS No. 3 test piece (2 mm U-shaped slit test piece). Results 'Although the inventive examples have substantially the same hardness with respect to the comparative example. The impact value (J/cm2), however, the machinability VL1000 was larger and superior than the comparative example. Further, Examples 89 to 94 were made of bearing steel as a base material, and were softened by a fixed spheroidizing annealing treatment at 700 ° C for 20 hr, and the machinability 15 VL1000 was measured. As a result, although the inventive examples have substantially equal hardness compared to the comparative examples, the machinability VL1000 is large and superior to the comparative examples. 26 1306476 6 shock 値 long | 61,8 I CO 64.9 1 75.3 1 1 69.5 1 | 70.9 1 1 107.4 1 | 101.5 1 | 105· 9 | l 1 1 Hardness HV Lil§J σ> s | 308 1 1 307 1 CO s CO 1 266 1 CO to 1 276 1 CS3 ft Sj Machinability VL1000 CO o CO 00 tn CO cvi cn esi iH Chemical composition ("ass%) 〇丨0· 0013| 10.00151 10.00171 10.00161 丨0.00141 |0 0014 | 10.00361 [0.00301 丨0.0051 | |0. 0009 1 |0.0009 | [0. 0011 1 as |0. 0053 | |0. 0064 1 |0.0046 1 0. 0060 0.00S5 丨0.00521 |0. 0055 1 |0.00501 |0. 0056 1 丨0.0065 j LQQogJ 丨0· 0045 1 丨0. 026 | |0.031| [0.018 | |0. 033| 丨0.021 1 丨0.016| 丨0.030| 丨0.0211 |0.026| Γ〇. 029 ] | 034. 034| [0.0191 5 0.10 0.09 — Μ 1.83 m 0.33 0.29 0. 21 0.22 0.28 Ϊ 0.25 s f-4 0.97 0.91 o ΙΟ. 95 0.48 0.46 omr·^ O) GO 1 1 t 1 1 1 1 10.0024 1 1 1 1 1 1 丨0.0148] 1 1 10.02071 - 1 1 1 i 丨0.02131 1 tS 0.0067 0.0065 1 丨0.0094 | 丨0.00981 1 |0. 0034 1 丨0.00621 1 |0· 00581 10.0099 1 1 | 0.017 1 0.017 I 0.016 | | 0.019 | | 0.018 | 丨0.018 1 1 0.020 1 1 0. 014 1 I 0.016 | | 0.027 | | 0.020 | | 0. 024 | α. 0.013 |0.0131 0.013 |0.0131 10. 0141 l〇. 013] |0.018 ι |〇. 017 1 10.0171 丨0.0281 10·018| 丨0.017 | β o 0.74 0-74 0.72 0.71 0-79 0.59 0.55 0.57 0,51” 0-53 |0. 52 CO 0.19 0.20 0.19 0.21 o 0.19 CM ο 〇> ο 0,18 0.30 0.33 |〇. 21 0. 39 0. 40 0, 43 0· 39 0. 42 0. 39 〇. 22 0,19 0.20 0.98 0.98 0.99 1 Example I i Division invention Example 5 Comparative Example Invention Example Invention Example Comparative Example Invention Example 5 m Comparative Example m Inventive Example Comparative Example So S3 § S5 ς^ι s

27 1306476 INDUSTRIAL APPLICABILITY According to the steel of the present invention, by promoting the fracture of the body in the steel, the tool life and the surface roughness of the cutting surface can be improved in a so-called low carbon quick-cut steel having a c content of less than 0.15%, and even Good tool life and 5 cutting surface roughness are also obtained when Pb is not contained, and machinability can be improved in structural steel containing 0.15% or more of C, and mechanical properties can be deteriorated, especially The inhibition of the opposite sex is minimal, or the steel of the present invention can achieve good machinability compared to steel having the same degree of mechanical properties. Brief description of t-pattern 3 10 Figure 1 shows a schematic diagram of the straight-cutting test. Figure 1(a) shows the straight-through cutting test method, and Figure 1(b) shows the tool movement. Fig. 2 is a view showing a small-field rotary bending test piece having a notched portion. Fig. 3 is a schematic view showing the conditions of carbon immersion, Fig. 3(a) shows a mode diagram of carbon immersion 15 quenching, and Fig. 3(b) shows a pattern diagram of conditions of normalizing. [The main components of the diagram represent the symbol table] 1.. Cutting direction 3...Tools 2..Test material 4...Surface thickness measurement surface

Claims (1)

Announcement of the scope of patent application of this application · · Patent application No. 92116112 Patent application revision 93 September 1993 1. A steel with excellent machinability, including: c: 〇15~ [5%, Si: 3 % below, Μη: 0.01 to 3%, P: 0.001 to 0.2 5 <, S . 0.0 < 301 Ο 1 1%, Ζ η : 0.001 ～ 0.5%, Ν : 0.0001 ～0.02%, 〇: 0.0005 〇 〇5%. 2. If the steel with excellent machinability is in the scope of the patent application, according to the mass% Further included: Sn: 0.002~0.5%, Β: 0.0005~0.05%, Cr: 〇.〇1 ～7%, Μο:0·01 ～3%, V: 0.01 ～3%, Nb: 0.001 10 〇 .2%, Ti: 0.001 to 0.5%, W: 0.01 to 3%, Ni: 0,05 to 7%, Cu: 0.02 to 3%, A1: 0.001 to 2%, Ca: 0.0002 to 0.01%, Zr: 0.0003 to 0.5%, Mg: 0.0002 to 0.02%, Te: o.ooi to 0.5%, Pb: 〇.〇1 to 〇_7%, Bi: 〇.〇1 to 〇7% of one or two the above. 15 3. A steel having excellent machinability as in the second application of the patent application, wherein Ni% 2Cu% is satisfied when containing 0.3% of Cu in soil. 29