Displaying method of hot-rolled product austenite grains

A technology of austenite grain and display method, which is applied in the field of grain size inspection and can solve the problems of mixed crystals easily appearing in grain size

Inactive Publication Date: 2019-07-19
石钢京诚装备技术有限公司
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, some customers of hot-rolled materials proposed that the austenite grain size should be at 930°C or above, and the heat preservation time should be 3h or above, and the inspection should be carried out after water cooling, complete hardening and quenching. Using the above method to check the grain size is prone to mixed crystal phenomenon, and the pass rate is only 63%. about

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Displaying method of hot-rolled product austenite grains
  • Displaying method of hot-rolled product austenite grains
  • Displaying method of hot-rolled product austenite grains

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1 and comparative example 1

[0026] Example 1 and Comparative Example 1: The display method of the austenite grains of the hot-rolled material is specifically described as follows.

[0027] Two samples were taken from the 18CrNiMo7-6 hot-rolled material, namely sample 1 and sample 2. Sample 1 was loaded into the heating furnace at a furnace temperature of 500 ° C, and the temperature was raised to 930 ° C with the furnace, and the heating time was 65 minutes; sample 2 was loaded into the furnace; sample 1 and sample 2 were kept together for 4 hours; to room temperature. After heat treatment, samples 1 and 2 were cut to 1.0mm, ground and polished, and then corroded with supersaturated picric acid aqueous solution with 1 drop / 100mL of mercaptobenzothiazole added dropwise. The corrosion temperature was 75°C and the corrosion time was After 20s, wipe the sample with absorbent cotton; repeat the corrosion until the grain boundary corrosion is clear. Sample 1 is the sample of this embodiment, and sample 2 is ...

Embodiment 2 and comparative example 2

[0028] Example 2 and Comparative Example 2: The display method of the austenite grains of the hot-rolled material is specifically described as follows.

[0029] Take 2 samples from the 45H hot-rolled material. Sample 1 was loaded into the heating furnace at a furnace temperature of 480 ° C, and the temperature was raised to 960 ° C with the furnace, and the heating time was 70 minutes; After heat treatment, the sample was cut to 1.2 mm, ground and polished, and corroded with a supersaturated picric acid aqueous solution with 2 drops / 100 mL of cetylamine added dropwise. The corrosion temperature was 70 °C and the corrosion time was 25 s. Repeat the corrosion until the grain boundary corrosion is clear. Sample 1 and sample 2 were observed and graded with a metallographic microscope at 100 times magnification. The grain size rating of sample 1 is 7.0, the grain size is uniform, and there is no mixed crystal grain; the grain size rating of sample 2 is 6.5-3, the grain size is un...

Embodiment 3 and comparative example 3

[0030] Example 3 and Comparative Example 3: The display method of the austenite grains of the hot-rolled material is specifically described as follows.

[0031] Take 2 samples from the 22CrMo hot-rolled material. Sample 1 was loaded into the heating furnace at a furnace temperature of 470 ° C, and the temperature was raised to 940 ° C with the furnace, and the heating time was 60 minutes; After the sample is cut to 0.8mm, ground and polished, it is corroded with a supersaturated picric acid aqueous solution with 1 drop / 100mL of benzotriazole added dropwise. The corrosion temperature is 80°C and the corrosion time is 15s. Wipe the sample with absorbent cotton; repeat the corrosion until the grain boundary corrosion is clear. Sample 1 and sample 2 were observed and graded with a metallographic microscope at 100 times magnification. The grain size rating of sample 1 is 7.0, the grain size is uniform, and there is no mixed crystal grain; the grain size rating of sample 2 is 7-3....

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention discloses a displaying method of hot-rolled product austenite grains. The displaying method includes the steps that (1) a sample is taken, specifically, the sample is taken from a hot-rolled product to be detected; (2) heat treatment is carried out, specifically, the sample is loaded into a heating furnace under the furnace temperature of 500 DEG C or below and heated to 930 DEG C orabove with the furnace, heat preservation is carried out for 3 hours or above, and the sample is out of the furnace to be water-cooled; and (3) corrosion is carried out, specifically, after heat treatment, the sample is cut, ground, polished, and then corroded by a corrosive agent until a grain boundary is corroded to be clear. According to the displaying method of the hot-rolled product austenite grains, by changing the charging temperature of 930 DEG C or above, the charging sample at 500 DEG C or below is adopted to be heated slowly with the furnace, thus carbides in the hot-rolled productare separated out preferentially along the grain boundary, growth of the austenite grains can be prohibited effectively, the smaller grains are obtained, thus the grain size is changed from a mixed-grain state to a uniform-grain state, coarse grains are changed to the fine grains, the inspection qualification rate of the hot-rolled product austenite grain size is effectively increased, and the qualification rate reaches 90% or above.

Description

technical field [0001] The invention relates to the field of grain size inspection, in particular to a method for displaying austenite grains of a hot-rolled material. Background technique [0002] The inspection of austenite grain size of hot-rolled materials produced by various domestic enterprises is mainly based on GB / T6394-2017 "Metal Average Grain Size Inspection Method", and the laboratories of various enterprises usually use the direct hardening method in this method to inspect austenite grain size. According to this method, the hot-rolled material is usually heat-treated after the furnace reaches the set temperature, and the pass rate of the austenite grain size is greater than 95%. However, some customers of hot-rolled materials proposed that the austenite grain size should be at 930°C or above, and the heat preservation time should be 3h or above, and the inspection should be carried out after water cooling, complete hardening and quenching. Using the above metho...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): C21D6/00C23F1/28
CPCC21D6/00C23F1/28
Inventor 宋慰威金景峰
Owner 石钢京诚装备技术有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap