A rolling process favorable for spheroidizing annealing of cr and mo steel

A process and annealing technology, applied in the field of metallurgy, can solve undisclosed problems

Inactive Publication Date: 2015-11-04
NORTHEASTERN UNIV LIAONING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In summary, for Cr and Mo steel products, there is no published research report on the control technology of the rolling process that is beneficial to spheroidizing annealing

Method used

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  • A rolling process favorable for spheroidizing annealing of cr and mo steel
  • A rolling process favorable for spheroidizing annealing of cr and mo steel
  • A rolling process favorable for spheroidizing annealing of cr and mo steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A steel plant adopts 325mm×280mm bloom continuous casting-blooming-wire rolling process to produce Φ13mm wire rod for high-strength bolts. The steel grade and composition are shown in Table 1.

[0026] Table 1 Grades and compositions of steel grades

[0027] Grade C Si mn P S Cr Mo SCM435 0.35 0.2 0.65 0.013 0.007 0.95 0.2

[0028] (1) Open the billet after continuous casting. During the billet opening process, the heating temperature is 1100°C and the heating time is 7 hours;

[0029] (2) Roll the steel billet after billeting. During the rolling process, the rolling temperature is 1050°C, the final rolling temperature is 875°C, and the spinning temperature is 800°C; hold at 850°C for 1 hour, and corrode after quenching to obtain Austenite The comparison of bulk grains such as image 3 As shown, it can be seen from the figure that image 3 (b) The medium austenite particles are more refined and homogeneous;

[0030] (3) After roll...

Embodiment 2

[0035] A steel plant adopts the 325mm×280mm bloom continuous casting-blooming-wire rolling process to produce Φ10mm wire rod for high-strength bolts. The steel grade and composition are shown in Table 1.

[0036] (1) Open the billet after continuous casting. During the billet opening process, the heating temperature is 1130°C and the heating time is 5 hours;

[0037] (2) Roll the steel billet after billeting. During the rolling process, the rolling temperature is 1080°C, the final rolling temperature is 895°C, and the spinning temperature is 815°C; hold at 850°C for 1 hour, and corrode after quenching to obtain Austenite The comparison of bulk grains such as Figure 5 As shown, it can be seen from the figure that Figure 5 (b) The medium austenite particles are more refined and homogeneous;

[0038] (3) After the steel billet is rolled, it is rapidly cooled to 600°C at a cooling rate of 10°C / s, and then kept warm on the roller table cooling line until about 300°C, and the ro...

Embodiment 3

[0044] A steel plant adopts the 325mm×280mm bloom continuous casting-billet opening-wire rolling process to produce Φ8mm wire rods for high-strength bolts. The steel grades and compositions are shown in Table 1.

[0045] (1) Open the billet after continuous casting. During the billet opening process, the heating temperature is 1110°C and the heating time is 6 hours;

[0046] (2) Roll the steel billet after billeting. During the rolling process, the rolling temperature is 1070°C, the final rolling temperature is 885°C, and the spinning temperature is 810°C; hold at 850°C for 1 hour, and corrode after quenching to obtain Austenite The comparison of bulk grains such as Figure 7 As shown, it can be seen from the figure that Figure 7 (b) The medium austenite particles are more refined and homogeneous;

[0047] (3) After the steel billet is rolled, it is rapidly cooled to 570°C at a cooling rate of 15°C / s, and then kept warm on the roller table cooling line until about 330°C, an...

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Abstract

The invention belongs to the technical field of metallurgy and particularly relates to a rolling process beneficial to spheroidizing annealing of a Cr and Mo steel. The rolling process is carried out according to the following steps of: carrying out cogging, rolling and spinning on a continuously cast steel billet; then always carrying out heat preservation to about 300 to 350 DEG C on a roll table cooling line and carrying out coil collection so as to obtain a Cr and Mo steel rolled product. According to the invention, by cogging heating control, steel rolling temperature control and after-rolling cooling control, segregation at the position of one second of R and center segregation are improved, grains are refined and growth of abnormal grains is avoided. Meanwhile, generation of large granular ferrite and pearlite is controlled, martensite is controlled below 35 percent; tissues mainly comprising bainite is formed, and carbide of the tissues is more uniformly distributed on a matrix. Moreover, according to a product produced by using the process, time of spheroidizing annealing is greatly shortened, an annealing process is simplified and spheroidized cementite is more dispersively and finely distributed.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a rolling process beneficial to the spheroidizing annealing of Cr and Mo steels. Background technique [0002] Adding metal element Cr to steel can significantly improve the strength, hardness and wear resistance of steel, and adding metal element Mo can refine the grain of steel, improve hardenability and heat strength, and maintain sufficient strength at high temperatures and the effect of creep resistance. Therefore, steel containing Cr and Mo elements has good hardenability, low temperature impact toughness, strong fatigue strength and impact resistance, and is generally used to produce high-end steel products such as molds, gears, bearings, such as 35CrMo, 42CrMo, etc. can produce high-strength bolts for 12.9-grade automobile engines. Since the engine cylinder head and connecting rod bolts are subjected to high-frequency alternating loads during the operatio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21B37/74C21D8/00C21D1/32
Inventor 朱苗勇徐东田新中刘振民唐正友张素萍祭程回之旭罗森邱木生
Owner NORTHEASTERN UNIV LIAONING
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