Steel for 40CrNiMo high-strength bolt and preparation method of steel

A technology of high-strength bolts and steel ingots, applied in the field of medium-carbon high-strength alloys, can solve the problems of unfavorable scale and economy in the field of high-strength bolts, the inability to apply in the field of ordinary fasteners, and the impact of no mention, so as to improve the comprehensive yield of products , Avoid white spot precipitation, improve the effect of cutting performance

Inactive Publication Date: 2021-01-26
宝钢特钢长材有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This invention is mainly applicable to the main shaft of wind turbines. The residual elements such as materials P and S are low, and the smelting and forming process adopts electroslag remelting and forging forming methods, which also results in high production costs and cannot be applied in the field of ordinary fasteners.
In addition, this variety does not mention the influence of a certain content of sulfur in steel on cutting processing.
[0005] In summary, the current production method of 40CrNiMo steel is not conducive to the large-scale and economical needs of high-strength bolts in the fastener industry, but a preparation process is simple, easy to cut, excellent in performance and quality, and the production cost can be reduced. Controlled production methods have become the hot spot of current research

Method used

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  • Steel for 40CrNiMo high-strength bolt and preparation method of steel
  • Steel for 40CrNiMo high-strength bolt and preparation method of steel
  • Steel for 40CrNiMo high-strength bolt and preparation method of steel

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Experimental program
Comparison scheme
Effect test

preparation example Construction

[0046] The above-mentioned 40CrNiMo high-strength bolt steel can adopt the following preparation method, comprising the following steps:

[0047] S1: According to the above-mentioned metering ratio of steel elements, the molten steel is obtained by electric furnace smelting and out-of-furnace refining;

[0048] S2: performing vacuum degassing on the molten steel, and then performing die casting to obtain a die cast steel ingot;

[0049] S3: The die-cast steel ingot is rolled into a billet with a 750 rolling mill, and the first billet is rolled and then cooled slowly;

[0050] S4: hot rolling the bloom to obtain the 40CrNiMo high-strength bolt steel.

[0051] The specific operation of step S1 is:

[0052] Electric furnace smelting is used to remove P in the slag during the oxidation period, and the slag is clean. After the slag is discharged, deoxidizer and lime are added to make the slag uniform; the end point [C]≤0.05%, [Si]≤0.05%, and the tapping temperature is 1640~1690℃ ;...

specific Embodiment

[0061] Table 1 is a process parameter table

[0062]

[0063] Table 2 is the chemical composition of each embodiment

[0064]

[0065] Table 3 is the low power tissue

[0066]

[0067] Table 4 is the performance of high-magnification tissue

[0068]

[0069] Table 5 is the mechanical properties

[0070]

[0071] The tensile strength and yield strength of the steel grade of the invention are far greater than the standard lower limit, and can fully meet the use requirements in the field of high-strength bolts. In addition, compared with the prior art (publication number CN103627969, publication number CN106435332), in the case of similar performance parameters, the preparation process is simpler and the production cost is greatly reduced. In addition, the addition of sulfur in the material greatly improves its cutting performance.

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Abstract

The invention discloses steel for a 40CrNiMo high-strength bolt. The steel comprises, by weight, 0.37%-0.44% of C, 0.17%-0.37% of Si, 0.50%-0.80% of Mn, smaller than or equal to 0.020% of P, 0.010-0.030% of S, 0.60%-0.90% of Cr, 1.25%-1.65% of Ni, 0.15%-0.25% of Mo and the balance Fe and inevitable impurities. The invention further discloses a preparation method of the steel for the high-strengthbolt. The steel and the preparation method is simple in process path, low in cost and high in efficiency, the S element is controlled to be 0.010-0.030% in component, and the cutting machining performance of the material can be effectively improved.

Description

technical field [0001] The invention relates to a medium-carbon high-strength alloy, in particular to a 40CrNiMo high-strength bolt steel and a preparation method thereof. Background technique [0002] As fasteners, bolts are widely used in construction machinery, transportation and other fields. With the continuous development of the industry, the quality requirements for bolts are becoming increasingly stringent, especially to prevent parts from stress fracture failure, which requires bolts to have higher strength. performance. Due to the addition of Cr, Ni, and Mo alloy components, 40CrNiMo steel can improve the strength and toughness of ferrite on the one hand, and form carbides at the same time, which can further prevent the growth of austenite grains and improve the tempering stability of steel. Excellent comprehensive performance is obtained during use. In addition, because different fields and different use environments have certain differences in the performance r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/44C22C33/04C21C7/076C21C7/10C21D8/06
CPCC21C7/076C21C7/10C21D8/065C22C33/04C22C38/02C22C38/04C22C38/44Y02P10/20
Inventor 林仁敢张成名徐惠松胡倩磊李阳张华平马宝国
Owner 宝钢特钢长材有限公司
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