A processing method for refining grains of 35crmo alloy steel

A processing method and technology of alloy steel, which are applied in the field of hot processing and subsequent heat treatment of steel materials, can solve the problems of microstructure inheritance, difficult to form new equalization, and achieve low stacking dislocation energy, easy dynamic recrystallization, and improved microstructure uniformity. Effect

Inactive Publication Date: 2019-08-27
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the newly formed phase is mainly flake austenite, the original coarse austenite grains will be recovered after austenitization, resulting in the inheritance of the structure; if the newly formed phase is mainly spherical austenite , then the original coarse austenite grains will be refined without organizational inheritance, but it is generally difficult to form new phases dominated by spherical austenite
(2) Use the method of austenite recrystallization to refine the grains. The recrystallized grains have a new phase, and there is no fixed phase relationship with the original coarse grains, so it can eliminate tissue inheritance, but the difficulty lies in determining the appropriate phase. Austenite recrystallization temperature and holding time

Method used

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  • A processing method for refining grains of 35crmo alloy steel
  • A processing method for refining grains of 35crmo alloy steel
  • A processing method for refining grains of 35crmo alloy steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The test uses a 35CrMo alloy steel ingot remelted in an intermediate frequency induction furnace, and its original grain size is ASTM No. 1.0, (the grain size is about 240 microns) such as figure 1 As shown, the experimental material was processed into cylindrical samples.

[0028] First, the sample was heated in a box-type resistance furnace at 10°C·s -1 The heating rate is increased to 1210°C, and the temperature is kept for 16min; then the temperature is increased at 10°C·s -1 The cooling rate is lowered to the deformation temperature of 1050 ° C, and the temperature is kept for 10 minutes; then 0.1s -1 The upsetting test was carried out with a strain rate of 0.35; after the upsetting deformation, it was immediately quenched in water to maintain the high-temperature deformation structure of the sample (such as figure 2 As shown, the grain size is 13.86μm); then put the sample into the cooled heating furnace, and heat up with the furnace at a heating rate of 20°C...

Embodiment 2

[0031] The test adopts the 35CrMo alloy steel ingot remelted in the medium frequency induction furnace, and its original grain size grade is ASTM No.1.0, such as figure 1 As shown, the experimental material was processed into cylindrical samples.

[0032] First, the sample is heated in a box-type resistance furnace at 10°C / s -1 The heating rate is raised to 1200°C and kept for 15 minutes; then at 10°C·s -1 The cooling rate is lowered to the deformation temperature of 1000 ° C, and the temperature is kept for 10 minutes; then the temperature is 0.01s -1 The upsetting test was carried out with a strain rate of 0.4; after the upsetting deformation, it was immediately quenched in water to maintain the high-temperature deformation structure of the sample (such as Figure 4 As shown, the grain size is 18.96μm); then put the sample into the cooled heating furnace, and heat up with the furnace at a heating rate of 20°C / s. When the temperature reaches 850°C, keep it for 30 minutes ...

Embodiment 3

[0035]The test adopts the 35CrMo alloy steel ingot remelted in the medium frequency induction furnace, and its original grain size grade is ASTM No.1.0, such as figure 1 As shown, the experimental material was processed into cylindrical samples.

[0036] First, the sample is heated in a box-type resistance furnace at 11°C / s -1 The heating rate was raised to 1200°C, and kept for 15 minutes; then at 9°C·s -1 The cooling rate is lowered to the deformation temperature of 1025 ° C, and the temperature is kept for 11 minutes; -1 The upsetting test was carried out with a strain rate of 0.35; after the upsetting deformation, it was quenched in water immediately to maintain the high-temperature deformation structure of the sample; then the sample was placed in a cooled heating furnace and heated at 21°C / s The rate increases with the temperature of the furnace. When the temperature reaches 860°C, keep it warm for 35 minutes and then quench it with oil. Ultrasonic quenching is carri...

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Abstract

The invention discloses a processing method of a refined 35CrMo alloy steel crystal grain. The processing method comprises following steps: re-melting 35CrMo alloy steel cast ingots in a medium frequency induction furnace to obtain a 35CrMo alloy steel sample with a required size; heating the sample in a box-type resistance furnace, maintaining the temperature, then subjecting the sample to a jumping-up test, after the jumping-up test, immediately quenching the sample in water to obtain a sample with high temperature deformed structures; quenching the sample with high temperature deformed structures in oil, cooling to the room temperature, and carrying out a cyclic ultrasonic quenching-tempering treatment to refine and homogenize the crystal grain tissues so as to obtained the refined 35CrMo alloy steel crystal grain. The microscopic defects of obtained crystal grain are obviously reduced; the size of the crystal grain can reach 10 [mu]m or less, the tissue uniformity is prominently improved, and the comprehensive properties of an alloy member can be strengthened.

Description

technical field [0001] The invention relates to the technical field of thermal processing and subsequent heat treatment of steel materials, in particular to a processing method for refining grains of 35CrMo alloy steel. Background technique [0002] 35CrMo alloy structural steel has high static strength, impact toughness and high fatigue limit; it has high creep strength and durable strength at high temperature, and its long-term working temperature can reach 500 ° C, so it is mainly used in manufacturing Important parts in various machines subject to impact, bending, and high loads. [0003] Due to the inhomogeneous deformation during the hot compression process, and the coarse grains and segregation of the original cast structure, the recrystallized structure is generally inhomogeneous. The 35CrMo steel used for load-bearing components has a strong tendency of microstructure inheritance. The primary task of grain refinement is to reduce and eliminate microstructure inheri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/18C21D1/04C21D8/00C22C38/02C22C38/04C22C38/22C22C38/20C22C38/44C22C38/42
Inventor 石琛周亚军毛大恒王三星
Owner CENT SOUTH UNIV
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