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Hollow seamless steel pipe for spring

A seamless steel tube, hollow technology, used in springs, low internal friction springs, springs/shock absorbers, etc., can solve the problems of insufficient durability, limited direction of durability improvement, inability to meet fatigue strength, etc., and achieve fatigue strength. High and durable effect

Inactive Publication Date: 2017-10-13
KOBE STEEL LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, in these technologies proposed so far, the required fatigue strength cannot be satisfied, and the durability is insufficient.
Especially in the higher stress region, there is a limit to the durability improvement of the technology proposed so far, and it is necessary to study other factors

Method used

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  • Hollow seamless steel pipe for spring
  • Hollow seamless steel pipe for spring
  • Hollow seamless steel pipe for spring

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 2

[0122] The molten steel with the chemical composition shown in Table 1 of Example 1 was smelted by a common smelting method, cast and billet-rolled to form a billet with a cross-sectional shape of 155 mm×155 mm. In addition, REM in Table 1 is added in the form of misch metal containing about 50% of La and about 25% of Ce.

[0123] Under the conditions of A to G shown in Table 4, a hollow blank pipe was obtained from the blank piece, and then cold rolled and stretched to produce a hollow seamless steel pipe with an outer diameter of 16 mm, an inner diameter of 8 mm, and a length of 3000 mm. Conditions A to F are a method in which a hollow billet is obtained by mechanical processing of the billet, and then hot-extruded to obtain a hollow billet tube. Condition G is a method of obtaining a bar steel by hot rolling the billet, and performing gun-hole drilling on the billet. Processing to obtain a hollow blank tube method. Condition E corresponds to the production method disclosed...

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Abstract

Provided is a hollow seamless steel pipe for spring which contains, by mass%, C: 0.2-0.7%, Si: 0.5-3%, Mn: 0.1-2%, Cr: over 0% but not greater than 3 %, Al: over 0 % but not greater than 0.1%, P: over 0% but not greater than 0.02%, S: over 0% but not greater than 0.02%, and N: over 0% but not greater than 0.02%, and the remainder which comprises iron and unavoidable impurities, wherein the uneven thickness rate calculated using formula (1) is equal to or less than 7.0%. Uneven thickness rate = (maximum thickness-minimum thickness) / (average thickness) / 2*100 (1)

Description

technical field [0001] The present invention relates to a hollow seamless steel pipe for springs, and more particularly to a hollow seamless steel pipe for high-strength springs suitable for manufacturing hollow-shaped steel suspension springs used in automobiles and the like. Background technique [0002] In recent years, with the increasing demand for light weight and higher output power of automobiles aimed at reducing exhaust gas and improving fuel efficiency, suspension springs, valve springs, clutch springs, etc. used in suspension systems, engines, clutches, etc. , also working on high stress designs. Therefore, these springs tend to increase the load stress further in the direction of higher strength and smaller diameter. In order to cope with this tendency, there is a strong demand for a spring steel having higher performance also in terms of fatigue resistance and damping resistance. [0003] In addition, in order to achieve weight reduction while maintaining fat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C22C38/38C22C38/58F16F1/02C21D8/10
CPCC21D8/10C21D8/105C21D9/02C21D9/08C22C38/00C22C38/001C22C38/04C22C38/06C22C38/34C22C38/38C22C38/46C22C38/50C22C38/58F16F1/021F16F1/043
Inventor 高知琢哉畑野等丰武孝太郎
Owner KOBE STEEL LTD