JPH02170948A - Stainless steel having excellent cold forgeability - Google Patents

Abstract

PURPOSE:To obtain the subject steel having excellent workability in cold forging and furthermore having good corrosion resistance and electromagnetic characteristics by regulating the compositional critical value. CONSTITUTION:A stainless steel constituted of, by weight, <=0.015% C, <=0.10% Si, <=0.30% Mn, <=0.030% P, <=0.015% S, 4 to 20% Cr, >0.03 to 0.20% Al, <=0.020% N, <=0.0050% O and the balance Fe with impurities is prepd. If required, one or more kinds among <=1.5% Nb, <=1.5% Ta, <=1.5% Ti, <=1.5% Zr and <=1.5% V are added to the compsn. Or, according to necessary, one or more kinds among <=2.0% Cu, <=3.0% Ni and <=5.0% Mo are added thereto. In the same way, one or more kinds among 0.03 to 0.30% Pb, 0.002 to 0.020% Bi, 0.002 to 0.020% Ca, 0.01 to 0.20% Te and 0.03 to 0.30% Se are added thereto at need.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention has excellent cold forging properties and corrosion resistance, as well as excellent electromagnetic properties. In particular, good workability by cold forging is required, and at the same time, corrosion resistance and The present invention relates to stainless steel with excellent cold forgeability, which is suitably used as a material for electromagnetic parts and the like which are required to have good electromagnetic properties. (Prior Art) Conventionally, materials based on pure iron, for example, have often been used as materials for electromagnetic parts that require good electric m% characteristics (for example, "Revised 4th Edition Complete Flexibility Handbook") Published December 1981, 208, Japan Institute of Metals, Yosen No. 10
Pages 25 to 1062 19-6i Materials J, "Chemical Handbook Applied Handbook ■ Materials Cotton" October 1, 1986
58 Published by Nippon Kagaku Yoshin No. 1O21W-Page 1037 r13.8 Magnetic Materials. ). (Problems to be Solved by the Invention) However, the above-mentioned pure iron-based materials have poor corrosion resistance and are prone to corrosion, which may reduce the durability and reliability of IF1M products. (Objective of the Invention) The present invention was made in view of such conventional problems, and in particular, it is required to have good workability when manufacturing by cold forging, and at the same time, The purpose is to provide a stainless steel suitable as a material for electromagnetic parts that is required to have good corrosion resistance and electromagnetic properties, and can maintain high reliability over a long period of time.

[Structure of the invention]

(Means for Solving the Problems) The stainless steel with excellent cold forgeability according to the present invention has, in weight percent, C: 0.015% or less, Si: o, io% or less,
Mn: 0.30% or less, P: 0.030% or less, S: 0
．． 015% or less, Cr: 4 to 20%, Al: more than 0.03 to 0.20%, N: 0.020% or less, O: 0.0
050% or less, and if necessary Nb: 1.5% or less. Ta: 1.5% or less, Ti: 1.5% or less, Zr: 1
．． 5% or less, V: one or more selected from 1.5% or less, Cu: 2.0% or less, Ni: 3.0% or less, M. : One or more selected from 5.0% or less, Pb: 0.03 to 0.30%, B
i: 0.002-0.020%. Ca: 0.002-0.020%, Te: 0.
01 ~ 0.20%, Se: 0.03 ~ 0.30%
Contains one or more types selected from the following, and the remainder F
The composition of stainless steel having excellent cold forgeability is used as a means for solving the above-mentioned conventional problems. Next, the reasons for limiting the composition (weight %) of the stainless steel with excellent cold forgeability according to the present invention will be explained. C: 0.015% or less C is the electromagnetic property when used as a material for electromagnetic parts,
In particular, C is an element that has a negative effect on coercive force, and is also an element that reduces toughness and deteriorates cold forgeability, so the upper limit of the C content is set to 0.015%. Sj: 0.10% or less Si has the effect of improving magnetic properties and corrosion resistance, but it is an element that worsens cold forging properties, so it is used to manufacture parts by cold forging, which contributes to improving one-dimensional accuracy. In order to improve the properties, the upper limit of the St content is set at 0.10%.
And so. Mn: 0.30% or less If a large amount of Mn is contained, cold fI buildability is impaired, so the upper limit of the Mn content is set to 0.30%. P: 0.030% or less If a large amount of P is contained, cold forgeability will deteriorate, so for this reason, the upper limit of the P content is set to 0.030%.
And so. S: 0.015% or less If a large amount of S is contained, cold forgeability will deteriorate, so for this reason, the upper limit of the S content is set to 0.15%. Cr: 4-20% Cr is an element that is effective in improving corrosion resistance as well as increasing volume resistivity (increasing ?11 air resistance).
In order to obtain such an effect, the Cr content was set to 4% or more. However, even if the Cr content exceeds 20%, a sufficient increase in volume resistivity cannot be observed, and rather leads to a decrease in the magnetic flux density B20, so the Cr content is set to 20% or less. Sentence A: Exceeding 0.03 to 0.20% An is an element that is effective in increasing volume resistivity, and is also effective in improving electromagnetic properties by reducing coercive force. 0.03 to obtain the effect of improving electromagnetic properties by increasing and decreasing coercive force.
%. However, 0.20
If the An content is more than 0.20%, the cold m permeability will deteriorate, so the An content is set to 0.20% or less. N: 0.020% or less N is T when used together with C as a material for electromagnetic parts
It is an element that has a negative effect on ILrj1 characteristics, especially coercive force, and is also an element that reduces toughness and worsens cold forgeability, so the upper limit of the N content is set to 0.02.
It was set to 0%. 0: 0.0050% or less 0 produces oxide-based inclusions and significantly deteriorates cold forgeability, and low oxygen content reduces coercive force and improves electromagnetic properties. , the upper limit of the 0 content was set to 0.0050%. For this reason, it is more preferable to adjust the upper limit of the zero content to 0.0020% or less. Nb: 1.5% or less, Ta: 1.5% or less, Ti: 1.
5% or less, Zr: 1.5% or less, V: 1. One or more selected from 5% or less of C and N are elements that cause deterioration of coercive force as described above, but in order to reduce the adverse effects of C and N, carbonitride-forming elements Nb, Ta, Ti, Zr
It is also desirable to add one or more types of V, if necessary, to refine the crystal grains. As mentioned above, when Ti is added to reduce the adverse effects of C and N on coercive force, this Ti promotes the formation of TiC and TiN, improving magnetic properties, cold forgeability, and toughness. This effect is similar for Nb, Ta, Zr, and V. However, if too much is added, cold forgeability is deteriorated, machinability is reduced, and workability is impaired, so even if added, the upper limit of each element is set to 1.596 or less. Cu: 2.0% or less, Nf: 3.0% or less, M O =
One or more elements selected from 5.0% or less Cu, Ni, and Mo are effective elements for improving corrosion resistance, so one or more of these elements may be added as necessary. It is good to add, however, if too much is added, cold forgeability will be deteriorated, so even if added, Cu is 2.0% or less, Ni is 3.0% or less, and Mo is 5.0% or less. It needs to be 0% or less. Pb: 0.03-0.30%, Bi: 0.002-0.
020%, Ca: 0.002-0.020%, Te:
0.01 ~ 0.20%, Se: 0803 ~ 0.30
% Pb, Bi, Ca, Te, and Se are effective elements for improving machinability. For example, after specifying the shape of a part by cold forging, Since it is an effective element for improving machinability when forming drill holes, it is also possible to add one or more of these elements as necessary to obtain such an effect. Good. However, if added in large amounts, it will reduce cold forgeability and deteriorate magnetic properties, so it is better to add within a range that does not impair these properties. For Pb, add 0.03.
~0.30%, 0.002-0.020 for Bi
%, 0.002 to 0.020% for Ca, 0.01 to 0.20% for Te, 0.0 for Se
It may be added as necessary in the range of 3 to 0.30%. (Action of the invention) The stainless steel with excellent cold forgeability according to the present invention has the above-mentioned composition, so it contains C, Si, Mn.
, P, S, N, and O have excellent cold forging properties, and A9. ,Nb,
The effect of adding appropriate amounts of Ta, Ti, Zr, and V and the regulation of C, N, and O has resulted in improved electromagnetic properties and finer grains. Corrosion resistance is also good due to the effect of adding appropriate amounts of Cr, Cu, Ni, and Mo, as well as Pb, Bi, and Ca. The machinability is also good due to the effect of adding appropriate amounts of Te and Se. (Example) After melting stainless steel with the composition shown in Table 1,
The electrical resistance, heavy density and coercive force of each stainless steel were measured, and the cold forgeability, corrosion resistance and machinability were also investigated using the evaluation methods shown in Table 2. , #Eating quality and machinability were evaluated respectively. These measurement results and evaluation results are shown in Table 3.As shown in Tables 1 to 3, in Comparative Examples No. 1, in which the Cr content is too low, the electrical resistance is small because the increase in volume resistivity is insufficient. , the corrosion resistance was also quite poor, and in Comparative Example No. 2, which had too high a C content and too much N content, the coercive force was quite large, resulting in poor magnetic properties and cold forging. In addition, in Comparative Examples No. 3 and 3, which have too much Al content, although the electrical resistance is high, the cold forgeability is extremely poor and the The machinability is also not very good, and furthermore, in the case of Comparative Example No. 014, which has too much Si content, the cold forgeability is extremely poor and the machinability is also not very good. Furthermore, in the case of Comparative Example No. 015, in which the An content is too low, the electric resistance is small and the coercive force is deteriorated. In some cases, the cold forgeability is extremely poor, the machinability is also not very good, and furthermore, the coercive force shows a large value and the electromagnetic properties are also extremely poor. This was recognized. On the other hand, in Example No. 1-11 of the present invention, the contents of C, Si, Mn, P, S, and NlO were regulated within appropriate ranges, and the content of Cr and A was appropriately set. , all have good electrical resistance, magnetic flux density, and magnetic properties, as well as good machinability, corrosion resistance, and cold forgeability.
By adding one or more of r and V, it is possible to prevent or further improve the magnetic properties caused by the addition of other alloying elements. By adding one or more of Pb, Bi, Mo, it is possible to prevent or further improve the corrosion resistance caused by the addition of other alloying elements. , T
It was confirmed that machinability can be further improved by adding one or more of the following.

【Effect of the invention】

The stainless steel according to the present invention has C: 0.01 in weight%.
5% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0.030% or less, S: 0.015% or less, C
r: 4-20%, AfL: over 0.03-0.20%,
N: 0.020% or less, O: 0.0050% or less, and if necessary, Nb: 1.5% or less, Ta: 1.5% or less. Ti: 1.5% or less, Zr: 1.5% or less, v: 1.5
% or less, and if necessary, Cu: 2.0% or less. One or more types selected from Ni: 3.0% or less, M O75, 0% or less, and P as necessary.
b: 0.03-0.30%, Bi: 0.002-0.
020%, Ca: 0.002-0.020%, Te: 0
．． 01-0.20%. Cold forging has particularly high dimensional accuracy and excellent productivity because it contains one or more selected from Se: 0.03 to 0.30%, and the balance is Fe and impurities. It has extremely good workability when manufacturing parts, and at the same time, the corrosion resistance and electromagnetic properties of the parts are also good, making it particularly suitable as a material for electromagnetic parts, and ensuring high reliability of electromagnetic parts over a long period of time. This brings about a remarkable effect in that it can be maintained for a long period of time.

Claims (1)

[Claims] (1) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, the balance being Fe and impurities. Stainless steel with excellent cold forgeability. steel. (2) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Nb: 1.5% or less, Ta
: 1.5% or less, Ti: 1.5% or less, Zr: 1.5%
A stainless steel with excellent cold forgeability, characterized in that it contains one or more selected from the following: V: 1.5% or less, and the balance consists of Fe and impurities. (3) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Cu: 2.0% or less, Ni
A stainless steel with excellent cold forgeability, characterized in that it contains one or more selected from: 3.0% or less, Mo: 5.0% or less, and the remainder consists of Fe and impurities. (4) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Pb: 0.03 to 0.30
%, Bi: 0.002-0.020%, Ca: 0.00
2 to 0.020%, Te: 0.01 to 0.20%, Se: 0.03 to 0.30%, and the remainder is Fe and impurities. Stainless steel with excellent cold forging characteristics. (5) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Nb: 1.5% or less, Ta
: 1.5% or less, Ti: 1.5% or less, Zr: 1.5%
One or more types selected from the following: V: 1.5% or less, Cu: 2.0% or less, Ni: 3.0%
A stainless steel with excellent cold forgeability, characterized in that it contains one or more selected from the following: Mo: 5.0% or less, and the balance consists of Fe and impurities. (6) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Nb: 1.5% or less, Ta
: 1.5% or less, Ti: 1.5% or less, Zr: 1.5%
Below, one or more types selected from V: 1.5% or less, Pb: 0.03 to 0.30%, Bi:
0.002-0.020%, Ca: 0.002-0.0
20%, Te: 0.01 to 0.20%, Se: 0.03 to 0.30% or two selected from
A stainless steel with excellent cold forgeability, which is characterized by containing at least 100% Fe and the remainder consisting of Fe and impurities. (7) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Cu: 2.0% or less, Ni
: 3.0% or less, Mo: 5.0% or less, and Pb: 0.03 to 0.3.
0%, Bi: 0.002-0.020%, Ca: 0.0
02-0.020%, Te: 0.01-0.20%, S
e: 1 or 2 selected from 0.03-0.30%
A stainless steel with excellent cold forgeability, which is characterized by containing at least 100% Fe and the remainder consisting of Fe and impurities. (8) In weight%, C: 0.015% or less, Si: 0.10% or less, Mn: 0.30% or less, P: 0
．． 030% or less, S: 0.015% or less, Cr: 4-2
0%, Al: over 0.03 to 0.20%, N: 0.020% or less, O: 0.0050% or less, and Nb: 1.5% or less, Ta
: 1.5% or less, Ti: 1.5% or less, Zr: 1.5%
One or more types selected from the following: V: 1.5% or less, Cu: 2.0% or less, Ni: 3.0%
Hereinafter, one or more types selected from Mo: 5.0% or less, furthermore Pb: 0.03 to 0.30%,
Bi: 0.002-0.020%, Ca: 0.002-0.020%, Te: 0.01-0.20
%, Se: 1 selected from 0.03 to 0.30%
A stainless steel with excellent cold forgeability, characterized by containing one or more species, with the remainder consisting of Fe and impurities.