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Quenching test method of austenite grain size of high-strength ship plate steel

A technology of austenite grain and inspection method, applied in the direction of particle size analysis, particle and sedimentation analysis, preparation of test samples, etc. Accuracy and other issues, to achieve the effect of easy hardening, complete austenite grains, and shortened inspection cycle

Active Publication Date: 2013-12-18
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the problems of hard hardening of steel samples, difficult corrosion of austenite and inaccurate grain evaluation results in the prior art, and to provide A quenching inspection method for austenite grain size of high-strength ship plate steel that is simple and easy to implement, can improve the hardenability of steel, promote the formation of austenite grains, shorten the inspection cycle, and improve the accuracy of evaluation results

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Quenching heat treatment for austenite grain display of high-strength ship plate steel containing 0.14% C, 0.5% Si, 0.9% Mn, 0.035% P, 0.035% S, and 0.015% Al.

[0023] A 20×20×20 mm metallographic sample of high-strength ship plate steel was taken, and the cross-section in the rolling direction of the steel plate was selected for grinding and mechanical polishing to Ra0.012mm.

[0024] Place the sample polished side up on a steel plate with a thickness of 3mm. Sprinkle carbon powder with a particle size of 80 mesh on the surface of the polished metallographic sample, with a thickness of 1mm, and lightly press the carbon powder covering layer with a thin steel sheet.

[0025] Raise the temperature of the heat treatment furnace to 930°C, open the furnace door, clamp one end of the steel plate on which the sample is placed with a clamp, and send it to the middle position in the furnace. Ensure that the edge of the sample on the steel plate is 32mm away from the heating e...

Embodiment 2

[0028] Quenching heat treatment for austenite grain display of high-strength ship plate steel containing C 0.17%, Si 0.48%, Mn 0.8%, P 0.029%, S 0.035%, Al 0.015%.

[0029] A 20×20×20 mm metallographic sample of high-strength ship plate steel was taken, and the cross-section in the rolling direction of the steel plate was selected for grinding and mechanical polishing to Ra0.012mm.

[0030] Place the sample polished side up on a steel plate with a thickness of 2mm. Take carbon powder with a particle size of 80 mesh and spread it on the surface of the polished metallographic sample, with a thickness of 1mm, and lightly press the carbon powder covering layer with a thin steel sheet.

[0031] Raise the temperature of the heat treatment furnace to 935°C, open the furnace door, clamp one end of the steel plate on which the sample is placed with a clamp, and send it to the middle position in the furnace. Ensure that the edge of the sample on the steel plate is 35mm away from the he...

Embodiment 3

[0034] Quenching heat treatment for austenite grain display of high strength ship plate steel containing C 0.18%, Si 0.51%, Mn 0.85%, P 0.033%, S 0.036%, Al 0.016%.

[0035] A 20×20×20 mm metallographic sample of high-strength ship plate steel was taken, and the cross-section in the rolling direction of the steel plate was selected for grinding and mechanical polishing to Ra0.012mm.

[0036] Place the sample polished side up on a 2.5mm thick steel plate. Take carbon powder with a particle size of 80 mesh and sprinkle it on the surface of the polished metallographic sample with a thickness of 1mm, and lightly press the carbon powder covering layer with a thin steel sheet.

[0037] Raise the temperature of the heat treatment furnace to 940°C, open the furnace door, clamp one end of the steel plate on which the sample is placed with a clamp, and send it to the middle position in the furnace. Ensure that the edge of the sample on the steel plate is 40mm away from the heating elem...

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Abstract

The invention provides a quenching test method of austenite grain size of high-strength ship plate steel. The method comprises the following steps: grinding and polishing a ship plate metallographic specimen, placing the metallographic specimen on a steel plate with the test surface being upwards, and uniformly paving and scattering carbon powder on the test surface; placing the steel plate and the metallographic specimen in a 930-940 DEG C heat treatment furnace, heating up to 900-930 DEG C, maintaining the temperature for 1-1.5 hours, and quenching the steel plate and the metallographic specimen into water; grinding and polishing the carbon powder covering surfaces after the steel plate and the metallographic specimen are completely cooled, eroding the steel plate and the metallographic specimen into a 20% picric acid aqueous solution for 1-2 minutes, washing with water and drying the steel plate and the metallographic specimen, observing the austenite grain morphology under a metallographic microscope, and grading the grain size. According to the quenching test method provided by the invention, the steel matrix surface is prevented from being oxidized, the formation of a hardening layer on the steel sample surface is promoted, so that the austenite grain morphology of the steel is easily and completely shown so as to provide good microstructure morphology for accurately evaluating the grade of the austenite grain size of the steel, the energy consumption can be reduced, the corrosive material is saved, the test period is shortened and the inspection efficiency is improved.

Description

technical field [0001] The invention belongs to the field of metallurgical analysis, in particular to a quenching inspection method for austenite grain size of low-carbon high-strength ship plate steel. Background technique [0002] The austenite grain size of steel directly affects its strength and toughness. Therefore, low-carbon high-strength ship plate steel usually needs to test its austenite grain size. The existing austenite grain inspection of this kind of steel at home and abroad is to use carburizing method, simulated carburizing method, direct hardening method and other heat treatment processes to form austenite grain of steel, and then use gold The phase corrosion method shows austenite grains and evaluates its grain size level. [0003] The composition of high-strength ship plate steel is generally: C≤0.18%, Si≤0.50%, Mn0.90-1.60%, P≤0.025%, S≤0.025%, Al 0.015-0.055%. Due to the low carbon content in the steel, the structure is not easy to harden, so the aust...

Claims

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Application Information

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IPC IPC(8): G01N15/02G01N1/28
Inventor 隋晓红张鹏远
Owner ANGANG STEEL CO LTD
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