Non quenched and tempered nitrocarburized parts

A soft nitriding part, non-quenching and tempering technology, applied in the direction of centrifugal force-resistant rotating parts, furnace types, furnaces, etc., can solve problems such as surface cracks, and achieve high bending fatigue strength and excellent bending correction effect.

Active Publication Date: 2019-03-08
NIPPON STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, when the HV hardness at the position 0.05 mm from the surface of the crankshaft is set to 410 or more, cracks will occur on the surface layer during bending correction.

Method used

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  • Non quenched and tempered nitrocarburized parts
  • Non quenched and tempered nitrocarburized parts
  • Non quenched and tempered nitrocarburized parts

Examples

Experimental program
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Embodiment

[0132] Steels A to N having the chemical compositions shown in Table 1 were smelted in a 70-ton converter, continuously cast, and then initially rolled into billets with cross-sectional dimensions of 180 mm×180 mm.

[0133] Next, each billet was hot-forged at a heating temperature of 1200° C. and a final temperature of 1000 to 1050° C., and processed into a steel bar with a diameter of 90 mm. The steel bar after hot forging is left to cool in the atmosphere and cooled to room temperature.

[0134] Steels A to H in Table 1 are steels whose chemical compositions are within the range specified in the present invention, and steels I to N are steels whose chemical compositions are outside the range specified in the present invention.

[0135] [Table 1]

[0136] Table 1

[0137]

[0138] The steel bar with a diameter of 90 mm thus obtained was heated to 1200° C., and hot forged at a final temperature of 1,000 to 1,050° C. to produce a steel bar with a diameter of 50 mm. The st...

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Abstract

A non-quenched and tempered nitrocarburized part, the chemical composition of the blank steel is calculated in mass%, C: 0.35-0.50%, Si: 0.10-0.35%, Mn: 2.3-2.8%, S≤0.10%, N : 0.0030~0.0250%, Cu: 0~1.0%, Mo: 0~0.3%, Ni: 0~0.5%, Ti: 0~0.020%, balance: Fe and impurities, 3.10≤(0.316C+0.122)× (0.7Si+1)×(5.1Mn‑1.12)×(0.364Ni+1)×(2.16Cr+1)×(3Mo+1)≤6.00, P, Al and Cr in impurities are P≤0.08% , Al≤0.05% and Cr<0.20%; in the stress concentration part, the HV hardness at the position 0.05mm away from the surface is 410-480, the HV hardness at the position 1.0mm away from the surface is above 200, and the depth of the compound layer is below 5μm; and the blank The metallographic structure is bainite. The non-tempered nitrocarburized part has excellent bend correction and high fatigue strength.

Description

technical field [0001] The invention relates to non-tempered nitrocarburized components. More specifically, it relates to a non-tempered nitrocarburized part having high bending fatigue strength and excellent bending straightening properties. [0002] "Non-tempered nitrocarburized part" refers to a part that is subjected to nitrocarburized treatment without undergoing the so-called "tempering treatment", that is, "quenching-tempering treatment" after machining. Hereinafter, the above-mentioned "parts subjected to nitrocarburization treatment" will be simply referred to as "soft nitrocarburized parts". Background technique [0003] Crankshafts, connecting rods, etc. used in automobiles, industrial machinery, and construction machinery are manufactured by forging and machining into desired shapes, and then performing nitrocarburizing instead of quenching and tempering. . In particular, in the manufacture of automobile parts requiring high fatigue strength, wear resistance, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/00C22C38/60
CPCC22C38/00C22C38/60C21D9/28C21D9/30C23C8/32C23C8/80C22C38/06C22C38/38C22C38/42C22C38/58C21D1/06C21D2211/002C22C38/001C22C38/02C22C38/04C22C38/08C22C38/12C22C38/14C22C38/16F16C3/06F16C2204/74
Inventor 西谷成史高须贺干长谷川达也祐谷将人泷谷善弘
Owner NIPPON STEEL CORP
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