JPS6220853A - Machine structural steel - Google Patents

Abstract

PURPOSE:To manufacture a machine structural steel excellent in machinability by adding to a machine structural steel a specific amount of In as essential element or further other elements. CONSTITUTION:In is added and incorporated by 0.01-1.0% by weight to the machine structural steel containing 0.05-1.2% C, 0.1-2.0% Si and 0.1-2.0% Mn to improve machinability, or further, 0.01-0.5%, in total, of 1 or >=2 elements among S, Pb, Bi, Te, Se, Cd and Cu, or 1 or >=2 kinds among 0.1-5.0% Ni, 0.1-2.0% Cr and 0.05-1.0% Mo, or, in combination, both of the above two kinds are incorporated to the above steel. At this time, component regulation is carried out so that the additive quantity of S is 0.2-0.4% and the ratio Mn/S is >=4 and further the quantities of P, S and O, as impurities, are <0.010%, <0.015% and <0.010%, respectively.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to mechanical structural steel with excellent machinability, such as gears, bolts, U-bolts, retainers, shafts, rods, For various types of automobiles such as bottles.

This invention relates to mechanical structural steel with excellent machinability, which is used as a material for mechanical structural parts for industrial machinery, agricultural machinery, ships, etc.

(Prior Art) Conventionally, as mechanical structural steel applied to the above-mentioned applications, mechanical structural carbon steel (S-C) has been used.

5-CK), nickel chromium steel (SNC), nickel chromium molybdenum steel (SNCM), chromium steel (SCr)
, chromium molybdenum steel (SCM), manganese fi (SM
n), manganese chrome steel (SMnC), steel for bolts (S
NB), aluminum chromium molybdenum steel (SACM)
In order to improve the machinability of these materials, Pb
.

Machine structural steels to which Ca, S, etc. are added are also used.

(Problems to be Solved by the Invention) As mentioned above, conventional mechanical structural steels are applied in a wide range of fields, and Pb and Ca are used as needed.

Although S and the like are added to improve machinability, even better machinability is sometimes required depending on the application, shape, etc.

This invention was made in view of the above-mentioned conventional demands, and aims to provide a steel for machine structures that has better machinability.

[Structure of the Invention] (Means for Solving the Problems) The mechanical structural steel according to the present invention contains In of 0.1 to 1.0.
It is characterized by containing 0.05 to 1.2% of C and 0.1 to 1.2% of Si by weight.
2.0%, Mn: 0.1-2.0%, In: 0.01-
1.0%, and if necessary Ni: 0.1-5.0%
.

Cr: 0.1~2.0%, Mo: 0, 05~
1.0% of one or more of S, Pb, Bf, Te, Se, if necessary.

One or more of Ca and Cu in total 0.0
1 to 0.5%, also as necessary, Ti, V, Zr
, Nb, Tac 7) in a total of 0.03 to 3.0% of one or more of them, and also as necessary A: 0.0
1 to 0.06%, N: 0.01 to 0.025%,
The remainder consists of Fe and impurities, and if necessary,
Among impurities, P: 0.010% or less, S: 0.0
It is characterized by being regulated to 0:0.0010% or less, 15% or less (excluding cases where S is actively added as an element to improve machinability).

Next, the reason for limiting the composition range (weight %) of the mechanical structural steel with excellent machinability according to the present invention will be explained.

C: C is an essential element for ensuring strength as a mechanical structural steel, and for this purpose it is necessary to contain it in an amount of 0.05% or more. However, if contained in a large amount, the toughness will be reduced, so the upper limit is set at 1.2%.

Si: Si is an effective element as a deoxidizing agent and is an element necessary to prevent the occurrence of surface defects in steel ingots, and for this purpose it is necessary to contain it in an amount of 0.1% or more. However, if it is contained in a large amount, the toughness will decrease, so the upper limit should be set to 2.
Set to 0%.

Mn: Mn is effective as a deoxidizing agent and a desulfurizing agent, and not only improves the hardenability of steel, but also has the effect of preventing hot embrittlement due to S by forming sulfides such as MnS. In order to obtain such an effect, it is necessary to contain 0.1% or more.

However, if contained in a large amount, the machinability of steel deteriorates, so the upper limit is set at 2.0%.

In is an effective element for improving the machinability of steel for machine structural use, and it is necessary to contain it in an amount of 0.01% or more in order to obtain such an effect. However, if contained in a large amount, the toughness of the steel will be impaired, so the upper limit is set at 1.0%.

Ni: Ni is an element effective in improving the hardenability of mechanical structural steel and the toughness after quenching and tempering, and is included as appropriate depending on the required characteristics of the mechanical structural material. However, if it is contained in a large amount, machinability will be impaired, so 0.1 to 5.0%
It is recommended that the range be within the range of .

Cr: Cr is an effective element for improving the hardenability of mechanical structural steel and the strength after quenching and tempering, and is included as appropriate depending on the required characteristics of the mechanical structural material. However, if it is contained in a large amount, double carbides are formed and hardenability and machinability are impaired, so it is preferably in the range of 0.1 to 2.0%.

MO: MO is an effective element for improving the hardenability of mechanical structural steel and the strength and toughness after quenching and tempering.
Contain it as appropriate depending on the required characteristics of the machine structural material. However, if it is contained in a large amount, double carbides are formed, which reduces hardenability and machinability at the same time.
．． It is preferable to set it in the range of 0%.

S, Pb, Bi, Te, Se, Ca, Cu:S, Pb,
Bi, Te, Se, Ca, and Cu are all elements that are effective in improving the machinability of steel for machine structural use, and their combined addition with In, which is the machinability improving element mentioned above, improves the machinability of steel for machine structural use. This is effective in further improving machinability. but,
If too much, the manufacturability and toughness of the steel will be impaired, so the total content of each of these elements is preferably in the range of 0.01 to 0.5%.

When S is contained as an element for improving machinability, the S content should be in the range of 0.2 to 0.4% and M n
It is desirable to adjust the composition as necessary so that /S is 4 or more, and when S is not included, it is more desirable to keep the content as an impurity element to 0.015% or less.

In addition, Ti, V, and Zr are used to refine the grains of steel and further improve its strength.

A total of 0.01 to 3 of one or more of Nb and Ta
．． It is also good to add in the range of 0%, and in order to refine the crystal grains and improve toughness, add A: 0.01 to 0.0.
It is also good to add N in a range of 0.01 to 0.025%.

Furthermore, in order to further improve the toughness and machinability of steel, P: 0.010% or less, S:
0.015% or less (except when S is actively added as an element to improve machinability), O: 0.0O10
It is also desirable to regulate the amount below %, if necessary.

(Example 1) 50 kg of each steel having the components shown in Table 1 was melted in an induction furnace and then formed into ingots. After blooming and product rolling, cutting test pieces were taken. Then, Koyo, 1.11 is left as rolled, and Koyo, 2,3°22 is 845°C x 2h.
After normalizing by heating and cooling in air, the specimens were subjected to a cutting test under the conditions shown in Table 2. In this cutting test, tool life was investigated at a cutting speed of 50 m/min. As a result, as shown in Table 2 and Table 1, inventive steel Nos. 1 and 2, in which In was added to Comparative Steel No. and 11.12, respectively, had significantly increased tool life at a cutting speed of 50 m/min. It is clear that the steel of the present invention has significantly poor machinability. Also, p, s.

It is clear that the machinability of invention steels No. 3 and 3, in which the amount was regulated to be 0, is further improved.

(Example 2) Steels having the components shown in Table 3 were each melted in a 50 kg induction furnace and then formed into ingots, and after blooming and product rolling, cutting test pieces were taken. and 820-85 for each steel
Annealing was performed at 0°C.

Next, it was subjected to a cutting test under the conditions shown in Table 4. In this cutting test, tool life was investigated at a cutting speed of 40 m/min. The results are also shown in Table 3.

Table 4 As shown in Table 3, inventive steel Nos. 21 to 24, in which In was added to comparative steel Nos. 31 to 34, respectively, had significantly increased tool life at a cutting speed of 40 m/min. It is clear that the steel of the present invention has significantly superior stiffness. Also, P.

It is clear that the machinability of invention steel No. 25, in which the amount of S, 0 was regulated, was further improved.

(Example 3) 50 kg of each steel having the components shown in Table 5 was melted in an induction furnace, formed into an ingot, and then subjected to 1-segment rolling and product rolling, and then a cutting test was taken. Steel No. 41.51 was left as rolled, and the others were annealed at 750 to 850"C and then subjected to a cutting test under the conditions shown in Table 6. In this cutting test, the cutting speed was The tool life at 50 m/min was investigated.The results are also shown in Table 5.

As shown in Table 6 and Table 5, inventive steel Nos. 41 to 48, in which In was added to comparative steel Nos. 51 to 58, respectively, had significantly increased tool life at a cutting speed of 50 m/min. It is clear that the steel of the present invention has significantly poor machinability. Also, P.

It is clear that the machinability of the present invention steel No. 49, in which the amount of S, 0 was regulated, is further improved.

[Effects of the Invention] As explained above, the mechanical structural steel according to the present invention contains In in an amount of 0.1 to 1.0% by weight, and more preferably contains In in an amount of 0.1 to 1.0% by weight. :0.05~1.2
%, Si: 0.1-2.0%, Mn: 0.1-2.0%
, In: 0.01-1.0%, and Ni as necessary
: 0.1-5.0%, Cr: 0.1-2.0%,
Mo: 0.05 to 1.0% of one or more of S, Pb, and Bi, if necessary.

One or more of Te, Se, Ca, and Cu in a total of 0.01 to 0.5%, as well as Ti
, V, Zr, Nb, Ta) in a total of 0.03 to 3.0% of one or more of them, and A as necessary.
fL: 0.01-0.06%, N: 0.01-0.02
5%, the balance consists of Fe and impurities, and if necessary, among the impurities, P: 0.010% or less, S: 0.015% or less (S is actively added as an element to improve machinability) Except when (), O: 0.0010%
Since it has the composition regulated below, it has extremely excellent machinability and can be used to efficiently and accurately process mechanical structural parts such as gears, shafts, and pins. This has the effect of making it possible.

Patent applicant: Daido Steel Co., Ltd. Representative Patent Attorney Yutaka Oshio 1, Specification page 1, line 4 to page 3, line 11 of the following amendments August 19, 1985 Commissioner of the Patent Office Michi Uga Department 1. Indication of the case Patent Application No. 160063 of 1985 2. Name of the invention Machine structural steel 3. Relationship to the case of the person making the amendment Name of patent applicant (name) (371) Daido Steel Co., Ltd. 4 , Agent address (residence) Kobikikan Ginza Building, 2-8-9 Ginza, Chuo-ku, Tokyo 104 Telephone: 03 (5B?) 2781 (Representative) Telegraph: 03 (567) 7933 (GIN) 6, with amendment The increasing number of inventions (7) is corrected as described in claim (1), which is the feature to be corrected.

"2. Claims (1) Weight %: C: 0.05 to 1.2%, Si: 0.
1 to 2.0%, Mn: 0.1 to 2.0% as basic components, In is 0.01 to 1.0%.
A machine structural steel characterized by containing %.

(2) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01 to 1.0%, the remainder being Fe and impurities.

(3) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01-1.0%, and S, Pb, Bi
, Te, Se, Ca, and Cu in a total of o, oi ~ 0.5%, with the remainder being Fe and impurities.

(4) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0, 01-1, 0%, and Ni
:0.1~5.0%, Cr:0.1~2.0%, Mo:
A mechanical structural steel with excellent machinability as set forth in claim (1), comprising one or more of 0.05 to 1.0%, the balance being Fe and impurities. .

(5) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01~1.0%, and Ni: 0.1~
5.0%, Cr: 0.1-2.0%, Mo: 0
, 05 to 1.0%, and also S, Pb, and Bi.

Claim 1, characterized in that the composition consists of one or more of Te, Se, Ca, and Cu in a total of 0.01 to 0.5%, with the remainder being Fe and impurities. Machine structural steel with excellent machinability.

(6) S content is 0.2-0.4%, M n /
A mechanical structural steel with excellent machinability according to claim (3) or (5), wherein S is 4 or more.

(7) Among impurities, P: 0.010% or less, S:
Claims (2) and (3) that limit the content to 0.015% or less and 0.0010% or less! Machine structural steel (roll) 2 with excellent machinability as described in either item (4) or item (5), rIn of page 5, line 5 to line 6 of the specification is from 0.1 to "1.0% by weight" is corrected to "rIn of 0.01 to 1.0% by weight".

3. The "component range of steel for machine structural use" in lines 6 to 7 of page 6 is corrected to "more desirable range of composition of steel for machine structural use."

4. “Steel No., 2°3.2” on page 10, lines 8 to 9.
24 is corrected to “Steel No. 2.3, 12J.

5. 0.1 to 1.0% by weight of rIn on page 19, line 1
'' is corrected to 0.01 to 1.0% by weight of rIn.

that's all

Claims (7)

[Claims] (1) In weight%, C: 0.05-1.2%, Si: 0.
1 to 2.0%, Mn: 0.1 to 2.0% as basic components, In: 0.1 to 1.0%
A machine structural steel characterized by containing: (2) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01 to 1.0%, the remainder being Fe and impurities. (3) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01-1.0%, and S, Pb, Bi
, Te, Se, Ca, and Cu in a total of 0.01 to 0.5%, with the remainder being Fe and impurities. Machine structural steel with excellent machinability. (4) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01~1.0%, and Ni: 0.1~
5.0%, Cr: 0.1~2.0%, Mo: 0.05~
1.0% of one or more of them, the balance being Fe and impurities.
) Machine structural steel with excellent machinability. (5) Machine structural steel has C: 0.05 to 1.0 by weight%.
2%, Si: 0.1-2.0%, Mn: 0.1-2.0
%, In: 0.01~1.0%, and Ni: 0.1~
5.0%, Cr: 0.1~2.0%, Mo: 0.05~
1.0% of one or more of them, plus S, Pb
, Bi, Te, Se, Ca, or one or two of Cu
Claim (1) characterized in that the total amount of 0.01 to 0.5% is at least 0.01% to 0.5%, and the balance is Fe and impurities.
Machine structural steel with excellent machinability as described in Section 1. (6) Claim (3) or (5) in which the S content is 0.2 to 0.4% and the Mn/S is 4 or more.
Machine structural steel with excellent machinability as described in Section 1. (7) Among impurities, P: 0.010% or less, S:
Machinability according to any one of claims (2), (3), (4), or (5), which is regulated to 0.015% or less, O:0010% or less Excellent mechanical structural steel.