JPS59222529A - Manufacture of driving shaft using electric welded steel pipe - Google Patents

Abstract

PURPOSE:To manufacture inexpensively an electric welded steel pipe for a driving shaft with superior fatigue resistance by normalizing an electric welded steel pipe beforehand at a specified temp. when the diameter of the end of the pipe is reduced to manufacture a driving shaft. CONSTITUTION:An electric welded steel pipe is made of steel contg. 0.10-0.65% C, 0.05-0.60% Si and 0.25-2.0% Mn as essential components or further contg. <0.020% P, <0.008% S and 0.0010-0.005% Ca and/or 0.0010-0.030% REM. To the steel may be added one or more among 0.1-1.5% Cr, 0.15-0.5% Mo, <4.5% N and <0.1% V. When the diameter of the end of the electric welded steel pipe is reduced at the A3 transformation point of the steel or below to manufacture a driving shaft, the pipe is normalized beforehand at TN+ or -10 deg.C. TN is represented by equation 1. An electric welded steel pipe for a driving shaft with superior fatigure resistance can be manufactured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing drive shafts such as eve shafts.

Recently, efforts have been made to reduce the weight of automobile parts.

As one of the measures, progress is being made in making parts conventionally made of steel bars hollow, that is, making them into steel pipes. When manufacturing drive shafts (2) such as drive shafts as one of these components, we aim to reduce costs and reduce weight by using ERW steel pipes, and at the same time, because it is a safety component, welding and joints can be made easily. There is a need for a processing method with fewer limitations.

Conventionally, hollow drive shafts have mainly been produced by press-welding a forged part as shown in Fig. 1 to an ERW steel pipe 2, but ERW steel pipes! There is a possibility that fatigue cracks will occur from the intersection j of the seam weld 3 and the pressure weld part g.
Improvements have been requested. Therefore, as shown in Figure β,
It was desired that both ends of the steel pipe 2 be subjected to a drawing process (9) and used as an integrally molded steel pipe.

When seamless steel pipes (hereinafter referred to as SML pipes) are used as a material for an integrally molded drive shaft, the SML pipes have poor surface properties and are required to be cold cored before use, which increases manufacturing costs. Other drawbacks include large variations in wall thickness and a high possibility of surface decarburization.Furthermore, if the degree of cold working is insufficient, the inner surface of the tube will be poor, and cracks will occur from the inner surface of the tube during diameter reduction. The fatigue life of the shaft may be reduced.

In view of this situation, the present invention has made it possible to provide, at a low cost, an electric resistance welded steel tube for a drive shaft with excellent fatigue performance. That is, the present invention provides the following features: (1) When manufacturing a drive shaft by reducing the diameter of the tube end of 7♀ steel welded steel, the component composition is C; θ/θ to θB in weight percent.
5%+Sl; θ0S~θ θ%, Mn; 0
2. S~. The basic component is 2.0 Ch, and the remainder is essentially KFe.
After making an electric resistance welded steel pipe through a normal process using a steel made of steel, the pipe end is subjected to standard treatment at a temperature of TN±/θ°C before being subjected to diameter reduction processing below the A3 transformation point. A method for manufacturing a drive shaft using an electric resistance welded steel pipe.

However, TN: 9g-g. 2.237C+g3g. ．． !
;p+3θg2S]-3 ll9!3Mn+379.2
v-, 23Nl+. , 2(/θθCー.!;
)-g. 62cr+33Mo (The amount of each element is weight%) (2) When manufacturing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition is C; θ/θ to θ B.
5%, S+; θθS〜θθ%, Mn; 0,
2.5 to 2θq6 are the basic components, and P is 60.
．． 26% or less, S is limited to θθθg coefficient or less, and Ca
;θθθ/θ~ρθθS and REM;θθθ/θ~a
Using steel containing one or both of θ3θ and the remainder being substantially Fe, a stain-sewn steel pipe is made in a normal process, and then the pipe end is subjected to diameter reduction processing below the A3 transformation point. A method for manufacturing a drive shaft using an electric resistance welded steel pipe, characterized by subjecting it to standard heat treatment at a heat treatment temperature of TN±/θ°C.

However, TN:9gudo-2237ctenta3gjp+3θri9S i -3'1. 'l3Mn+379.2V-23
Ni +-2(/θθC-3'(+6Ni)-g
．． 2Cr+3.3Mo (The amount of each element is based on weight) (3) When manufacturing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition is based on weight and C; θ / θ ~ θ
Relationship, S1; θθS ~ θotsu θ crack, Mn; θ. 2.5~
The β and θ coefficients are the basic components, and P is θθ−? Below, S
are limited to 660g% or less, and KCa;0097
0~606.5% and REMθθθ10~θ03θ%
Contains one or both of KCr; θ/~/j%,
Mo; θ/3 ~ 05%, Ni; 13% or less, V; A method for manufacturing a drive shaft using an electric resistance welded steel pipe, which is characterized in that after the pipe is made into a steel pipe, the pipe end is subjected to standard heat treatment at a temperature of TN ±70°C before being diameter-reduced at a temperature below the A3 transformation point. Tanshi, TN: 9'l; 1.23.7c+93 and 5
P+Jθg2S1-3'1. '13Mn+379:2V
23N1+2(/θθC-5q+OtsuNi) g
, , 2cr+3.3Mo (the amount of each element is weight %).

The present invention will be explained in detail below.

First, the basic components of the steel used in the method of the present invention will be described.

If C is less than θ/, it is difficult to secure the required strength, and 66
If it exceeds 5%, problems arise in pipe formability, and furthermore, ductility and toughness during cold working decrease, so θ/~θ was selected.

The minimum amount of Sl required for killed steel is 865%, and if it exceeds θ6θ%, it will adversely affect elongation and toughness during diameter reduction processing, and surface flaws will occur due to hot rolling scale formation. I was disappointed.

"" Mn is required to be 25% or more of θ from the viewpoint of strength, and if it exceeds 2θ%'r, elongation and toughness during diameter reduction processing will deteriorate.

The above are the basic components of the steel used in the present invention, but by limiting P to 6926% or less and S to θθθg coefficient or less, better performance in elongation and toughness can be expected.

That is, since P causes component segregation in the steel sheet, it is limited to θθρθchi or less. Further, in order to reduce the amount of nonmetallic inclusions, S is set to θθθg% or less.

In addition, in the present invention, Ca; θθθ/θ ~ aθθ, 5%; REM; θθθ/θ
- θθ3θ or both may be contained.

Both of these lower limit values are combined with 02 below this value,
Its effect is not fully demonstrated.

Further, the upper limit value should be avoided because if it exceeds this value, extra inclusions will be generated in addition to bonding with S.

Furthermore, in the present invention, the following alloy components may be added singly or in combination, mainly for the purpose of improving strength or further toughness.

That is, Cr can be added in a range of 87 to 75%. If the ratio is less than 0θ/j%, the strength and hardenability improvement effect will be small, and if it exceeds /:j%, the toughness will decrease.

Father, 11. Iio can be added in a range of 975 to 95 to prevent coarsening of crystal grains at high temperatures and ensure elongation and toughness. If it is less than the θ/j ratio, it will not be possible to suppress the diffusion and precipitation of P, etc. to the grain boundaries, and if it exceeds θ5%, it will be expensive and there will be excess MoV (therefore, the toughness may deteriorate. KNi and V are used for the purpose of improving elongation and toughness.
They can be added within the range of qj%j% and θ/coefficient, respectively.

Addition of N1 in excess of this will be expensive, and addition of V in excess of this will combine with C in the steel and precipitate, resulting in deterioration of toughness.

Now, in the present invention, an electric resistance welded steel pipe is manufactured by a normal process using steel having the above-mentioned components. The normal process here refers to forming a strip into a tube shape, heating and melting both edges of the tube using high-frequency current, and pressing the squeeze roll 1 (a method of making tubes by pressure welding). Diameter reduction processing is performed as shown in Figure 2. When performing this processing at a temperature below the A3 transformation point, in order to uniformly deform the diameter reduction processing, the electric resistance welding part and other parts are It is necessary to carry out a final calcination (C-treatment before diameter reduction processing) to make it homogeneous.

The normalizing temperature of the electric resistance welded steel pipe used for drive shafts and the like is carried out at a temperature above the A3 transformation point determined by its component composition, and in the temperature range of A3 transformation point temperature + (3θ to 6°C). However, when the diameter reduction process shown in Figure 1 is performed using an ERW steel pipe that has been normalized in this temperature range, the ERW weld and weld will be unevenly deformed, and there will be flaws and inclusions on the inner surface of the pipe. In this case, the non-uniform deformation may cause cracks to occur starting from flaws or inclusions, which may significantly reduce the strength against torsional loads when used as a drive shaft.

According to research by the present inventors, the above-mentioned non-uniform deformation in the ERW weld is caused by the fact that normalizing treatment before diameter reduction processing coarsens the crystal grains in the heat affected zone (hereinafter referred to as HAZ). It was found that this was caused by

In order to prevent coarsening of crystal grains in the HAZ part, the present inventors set C; θ 0 coefficient; Si; θ2 θ%; Mn;
We conducted two types of diameter reduction processing experiments using a rotary swager and upsetting an ERW steel pipe whose basic component is θ8θ in a bright heat treatment furnace with a standard time of 3 minutes and varying the normalizing temperature. However, within the above temperature range of A3 transformation point temperature + (3θ~ and 6°C), if the normalization temperature is slightly higher,
It was found that the crystal grains in the HAZ area became coarse and non-uniform deformation occurred during diameter reduction processing. On the other hand, even if the normalization temperature is slightly lower within the same range, the size of the crystal grains will still be uneven, and the diameter will be reduced in the same way! It has one negative effect. However, it has been found that in this case, the effect on diameter reduction processing is small compared to the thick grains that occur noticeably in the KHkZ portion when the normalizing temperature is slightly higher. Therefore, the electric resistance welded steel pipes used for drive shafts etc.
In the case of ordinary steel materials, the normalization temperature should be set slightly lower.
Moreover, it was concluded that it was necessary to control the temperature within a narrow range.In the end, a uniform structure could be obtained, and the normal temperature range of 2.1 degrees Celsius, at which uniform diameter reduction could be achieved, was 30~jθ from the A3 transformation point temperature. ℃ high range, that is A3 transformation point temperature θ℃±
/θ℃.

Furthermore, as a result of examining the standard time in the bright heat treatment furnace by varying it from β to /θ minutes, it was found that as the standard time increased, the normal firing temperature range shifted to the lower temperature side, but the extent of this time dependence was It has become clear that it is better to control the normal firing temperature from the viewpoint of small size and standard efficiency. Figure 3 shows the relationship between normalization temperature and time. Normalizing temperature is related to the coarsening of crystal grains in the HAZ area, and uniform grains are obtained in the range surrounded by points A, B, C, and D in the figure, and therefore uniform deformation can be obtained during diameter reduction processing. I can do it.

On the other hand, when each component of the steel is expressed in terms of weight coefficient, the A3 transformation point temperature is determined by the following relational expression that takes into account the effects of Abbott's equation K Cr and Mo.

90g 2.23.7C+'13g, SP+30'1
9Si-3'l'13Mn+379c2V-23Ni
10, 2 (/θθC-, 5g→-OtsuNi) -g, 2C
r+3.3M.

However, according to the above knowledge, the appropriate firing temperature range is A3 transformation point temperature 10 degrees θ℃±/θ℃, so if (A3 transformation point temperature 10 degrees θ℃) is set as TN, baking will be : The W range of seat exposure is often TN±/θ℃.

In this case, TN=A3 transformation point temperature Transformation point temperature is added, so TN=9g-,2,23,7C+'13g5P+3θ
GutuSi -3'lg3Mn+3792V-,,2JN
i+, 2(/θθC, 5g+OtNi)-g, , 2Cr
+3'3M.

Express it as

The effects of the present invention will be illustrated in more detail with reference to Examples below.

'Table 1 in the Inuse row shows the condition of crystal grains in the HAZ part and diameter reduction processing (installation in a die) due to the difference in chemical composition and standard temperature conditions of carbon steel ERW steel pipes between the present method and the conventional method. 11.5 and the relationship between torsional fatigue strength. The standard conditions were 3 minutes in a Kouki 7i5 processing unit. Tsuta/~g is in the claims fl)K.

S~/, 2 is! Patent g) In (2) of the scope of the request, /3
~3g is a steel material and a comparison material having the same slope (3). In the classification column, temperature )' indicates that the temperature was normalized within the temperature range of the present invention, and N indicates that the temperature was normalized within the range outside this range.

Component Y is a component within the scope of the claims, and N is a steel type with a component outside f'L.

As shown in Table 1, no coarse grains were found in the HAZ part of the steel pipe normalized within the range of theoretical temperature TN±/θ°C. First, the workability was good in that no extreme breakage occurred during diameter reduction processing. On the other hand, an abnormal structure was observed under an optical microscope in the HAZ part of a steel pipe normalized in a range outside of TN±/θ℃, and based on this, the KHA during diameter reduction processing was
A recess is formed in the Z section. Furthermore, it is found that steel components containing impurities such as special KS in amounts exceeding the claimed range have poor torsional fatigue strength even if the normalizing temperature is appropriate and the shape during diameter reduction processing is good.

As described above, according to the present invention, when standardizing ERW steel pipes, the HAZ
Since the heat treatment problem of grain coarsening at the end can be solved, it is possible to supply ERW steel pipe with good surface quality at a lower cost than SML, and when performing diameter reduction processing on the end of the pipe as a drive shaft. Since it is possible to achieve uniform deformation and to suppress the occurrence of cracks due to non-uniform deformation, it is possible to manufacture a drive shaft with excellent strength.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional drive shaft, FIG. 3 is a diagram showing an integrally molded drive shaft, and FIG. 3 is a diagram showing appropriate standard conditions for an electric resistance welded steel pipe for a drive shaft. /...Forged products! ...ERW steel pipe 3...
Seam welded part Goo... Pressure welded part S - Intersection θ of the pressure welded part of seam welded part Procedure amendment for pipe end diameter reduction processing part (voluntary) July 26, 1980 Ship License Agency Tono 1, Indication of incident 1988 Patent Application No. 97737 2. Name of VC Ming's Manufacturing Method of Drive Shaft Using Steel Pipe 3, Relationship with Person Making Amendment Φ Patent Source Address 2-6 Otemachi, Chiyoda-ku, Tokyo No. 3 (66
5) Nippon Steel Corporation Name (Name Zeta Representative Take 1) Toyo 4, Agent 103-241-0441 Address 1-142-5, Nihonbashi Honmachi, Chuo-ku, Tokyo, day of the withdrawal order τ]
Yamamoto Amendment 6, the scope of the claims for the specific layer to be amended, and the detailed content of the prior amendment (1) The "Claims" will be amended as shown in the attached sheet. (2) Line 12 of page 5, line 7 of page 6, and line 5 of page 7 of the specification shall be corrected in accordance with the law. [is weight%, and if the 0 in the formula is negative, ignore it.'' (3) Correct page 12, line 16, as follows. 1+3.5Mo (However, if the value in parentheses is negative, ignore it)" (4) On page 13, line 6 is corrected as follows. l--8,2Or+3.5 Mo (Ignore this if it is within 0 or negative.) (5) Table 1 rTN (C IJ column and (t) Correct the numbers in the column j as follows: The component composition in weight percent is C; 0.10 to 0.
．． 65%, Eii; 0.05-0.60%. A steel having Mn; 0.25 to 2.0% as a basic component and the remainder substantially consisting of Fe is used to make an electric resistance welded steel pipe through a normal process, and then the end of the pipe is reduced in diameter below the A3 transformation point. A method for manufacturing a drive shaft using an electric resistance welded steel pipe, characterized in that the first step is standard treatment at a heat treatment temperature TN±10°C. However, T N: 948 2237C+ 438.5
P +30-49Si 34.43Mn+3'i',
92V 23Ni 12 (1000-54+6Ni)-
8,2Cr13.5M0 (The valley element content is 1% by weight.) (2) When manufacturing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition is C. :010~0.65%
, S i ;' CIo 5-0.60%. M n ; 0.25 to 20% as a basic component, and P
is limited to 0.020% or less, S is limited to o and oos%, respectively, Ca; 0.0010 to 0.005% and REM
; After making an electric ff copper tube by a normal process using steel containing one or both of 0.0010 to 0.030% and the remainder substantially consisting of Fe, the end of the tube is contracted at a temperature below the A3 transformation point. Driving equipment using electric resistance welded steel pipes, which is specially treated at a heat treatment temperature of TN±10°C before diameter processing.
Method for manufacturing l. However, TJ:948-223. '7C+438.5P
+30.498i 3443Mn+37.92V
23Ni+2(1000-54+6Ni) =8.2C
! r+3.5Mo (Valley element content is 1fit% If 0 in the formula is negative, ignore this. Component composition is C in weight%; 0.10 to 0.
65%, Si; 0.05-0.60%, Mn;
0.25-2.0% as the basic component and P as 0.02
0% or less, S is limited to below the o and oos ratios, and C!
a; 0.0010-0.005% and RKM; 0
．． 0010 to 0.030% of one or both of 1d,
Further VC-Cr; Ol"'-15X, MO;
0.15 to 05%, Ni; 4.5% or less, 7101% or less, containing one or more types, and the remainder substantially consisting of Fe, after making it into an electric resistance welded steel pipe through a normal process. ,
A method for manufacturing a drive shaft using an electric resistance welded steel pipe, characterized by subjecting the end of the pipe to standard treatment at a heat treatment temperature of TN±10° C. before reducing the diameter at a temperature below the A3 transformation point. Idanshi S'rl: 94B-223,'7
0+438.5P+30.4981-34.43Mn +37.92V-23N i+2 (LOOC54+6Ni) -8,20r + 3.5 Mo (The amount of each element is by weight %1 In the formula (), negative 11 I ignore this) do)"

Claims (3)

[Claims] (1) When manufacturing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition in weight percent is C; θ/θ ~ 0 B;
S%, Si; 0θS~040%, Mn; θ, 25~
, 20% as a basic component and the remainder being substantially KFe, a stain-stitched steel pipe is made by a conventional process, and then the pipe end is subjected to a heat treatment before being diameter-reduced at a temperature below the A3 transformation point. A method for manufacturing a drive shaft using an electric resistance welded steel pipe characterized by standard treatment at a temperature of TN±/θ°C.However, TN: 9g 1, 2.237C 1g 3g5
p+3θgu2S1-3guguEMn+379.2V-,2
3N1+, 2(/θθC-5q-+-OtsuNi) -g
,,2cr+3.3Mo (The amount of each element is based on weight) (2) When manufacturing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition is C; θ/θ ~ θ
%, S1; θθS〜θθ%, Mn; θ,, 2j
−βθ coefficient is the fundamental component, and P is less than or equal to θθβθ coefficient, S
Ca; 66976-9
60.5% and EM; θ0θ/θ to θθ30 ratio, or both, and the remainder is substantially KFe, and after making a stain-stitched steel pipe in a normal process, the end of the pipe is A.
3 Before diameter reduction processing below the transformation point ('(, heat treatment temperature TN
A method for manufacturing a drive shaft using an electric resistance welded steel pipe characterized by standard treatment at ±/θ°C. TN: 5'g -2,237C 10d3 5P
+3θg 2S1-3'l'13Mn+3"7.9.2V
=,23Ni +,,2(/θθCjg+OtsuNi)
g,,2Cr-(-3,3Mo (Amount of each element is based on weight) (3) When producing a drive shaft by reducing the diameter of the end of an ERW steel pipe, the component composition is C; 676 to 665 in weight%.
% Si; θθj ~ θ　θ begging M1〕; θ, 25-Jθ ratio is the basic component, and P is 9626% or less and S is 666%.
Each is limited to g% or less, Ca: 000/θ ~ θθθj%
and REM; θθθ/θ to θθ3θ, further KCr; θ/ to /j, Mo; θ/S to
After making an electric resistance welded steel pipe by a normal process using steel containing 7 types or β types or more of θj, Ni; A method for manufacturing a drive shaft using an electric resistance welded steel pipe, characterized in that before the pipe end is reduced in diameter below the A3 transformation point, it is subjected to standard treatment at a heat treatment temperature of TN +/θ°C.However, +TN: 9 da 1, 2,237C + M,! ;P+
3θg 5'Si -31I-g 3Mn+379.2V-
,,23Ni+,2(/θ0C-, 5g+OtsuNi)
-g,,2cr+3. sMo (Amount of each element is weight%)