Post-weld heat treatment method for Q345R steel plates for hot roll pressure container barrels

A post-weld heat treatment and heat treatment method technology, applied in the field of metallurgy, can solve the problems of mechanical properties and corrosion resistance, deterioration of steel plate corrosion resistance, etc., achieve good hydrogen sulfide corrosion resistance, good matching, ensure mechanical properties and resistance The effect of corrosion performance

Inactive Publication Date: 2018-10-26
WUYANG IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, plastic deformation produces a large number of defects such as dislocations and vacancies, which seriously deteriorates the corrosion resistance of steel plates.
In addition, after the reel is welded, the structure of the heat-affected zone has undergone tremendous changes, and the mechanical properties and corrosion resistance have decreased significantly.

Method used

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  • Post-weld heat treatment method for Q345R steel plates for hot roll pressure container barrels
  • Post-weld heat treatment method for Q345R steel plates for hot roll pressure container barrels
  • Post-weld heat treatment method for Q345R steel plates for hot roll pressure container barrels

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Experimental program
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Effect test

Embodiment 1

[0026] The thickness of the Q345R steel plate in this embodiment is 111mm, and the post-weld heat treatment method includes heating, heat preservation, and cooling procedures. The specific process steps are as follows:

[0027] (1) Heating process: the furnace loading temperature is 425°C, and the heating rate is 88°C / h when the temperature is higher than 425°C;

[0028] (2) Heat preservation process: the heat preservation temperature is 595°C, and the heat preservation time is 12 hours;

[0029] (3) Cooling process: After the heat preservation is over, the temperature is lowered in the furnace at a rate of 62 °C / h, and when the temperature is lowered to 405 °C, it is taken out of the furnace for air cooling.

[0030] The steel plate surface hardness after heat treatment in this embodiment is 182HB, and the weld seam surface hardness is 179HB; See figure 1 , the microstructure of the weld see figure 2 ;

[0031] The mechanical properties of the 1 / 2 position of the plate t...

Embodiment 2

[0035] The thickness of the Q345R steel plate in this embodiment is 135mm, and the post-weld heat treatment method includes heating, heat preservation, and cooling procedures. The specific process steps are as follows:

[0036] (1) Heating process: the furnace loading temperature is 396°C, and the heating rate is 82°C / h when the temperature is >425°C;

[0037] (2) Heat preservation process: the heat preservation temperature is 605°C, and the heat preservation time is 13 hours;

[0038] (3) Cooling process: After the heat preservation is over, the temperature is lowered in the furnace at a rate of 67°C / h, and when the temperature is lowered to 420°C, it is taken out of the furnace for air cooling.

[0039] The surface hardness of the steel plate after heat treatment in this embodiment is 188HB, and the surface hardness of the weld is 176HB; the microstructure of the steel plate and the weld is pearlite + ferrite, and the grain size is 10.5; the microstructure of the steel plate...

Embodiment 3

[0044] The thickness of the Q345R steel plate in this embodiment is 160mm, and the post-weld heat treatment method includes heating, heat preservation, and cooling procedures. The specific process steps are as follows:

[0045] (1) Heating process: the furnace loading temperature is 411°C, and the heating rate is 80°C / h when the temperature is >425°C;

[0046] (2) Heat preservation process: the heat preservation temperature is 615°C, and the heat preservation time is 14 hours;

[0047] (3) Cooling process: After the heat preservation is over, the temperature is lowered in the furnace at a rate of 70°C / h, and when the temperature is lowered to 398°C, it is taken out of the furnace for air cooling.

[0048] The surface hardness of the steel plate after heat treatment in this embodiment is 172HB, and the surface hardness of the weld is 166HB; the microstructures of the steel plate and the weld are pearlite + ferrite, and the grain sizes are 10.5 and 10 respectively; microstructu...

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Abstract

The invention discloses a post-weld heat treatment method for Q345R steel plates for hot roll pressure container barrels. The post-weld heat treatment method comprises the processes of steel plate heating, heat preservation and cooling. According to the post-weld heat treatment method, the post-weld heat treatment heating speed, the heat preservation time, the cooling speed and other processes arecontrolled, the good mechanical property of the steel plates is guaranteed, the interior microstructure coarsening and unevenness caused by hot roll of the Q345R (HIC) steel plates for the hot roll pressure container barrels are avoided, the internal defects are eliminated, and the mechanical property and the decay resistance of the steel plates and the welding heat effect zones are guaranteed. The treated steel plates are well matched with the 1 / 2 position of welding seams in the plate thickness direction in obdurability, the surface hardness is low, the mechanical property of the steel plates is stable, sulfuretted hydrogen corrosion resistance is good, and the post-weld heat treatment method is suitable for post-weld heat treatment production and checking of same-like steel plates withthe thicknesses ranging from 110 mm to 160 mm. The heat treatment method is simple and practical, and is suitable for volume production in plants.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a post-weld heat treatment method for a Q345R steel plate used for a cylinder body of a warm-rolled pressure vessel. Background technique [0002] Q345R (R-HIC) steel has low C, Mn, P, S content, and very few inclusions such as MnS, so it not only has good comprehensive mechanical properties, but also has strong resistance to hydrogen sulfide corrosion, and is widely used in petroleum , petrochemical and natural gas industries contain H 2 and wet H 2 S medium pressure vessels and reactors and other equipment. With the rapid development of large-scale pressure vessel equipment, due to the need for equipment safety, higher requirements are put forward for the thickness of Q345R (HIC) steel. [0003] At present, Q345R (HIC) thick plates are mainly concentrated in 110-160mm. Due to the influence of rolling equipment and steel plate thickness, the steel plate coils o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/50
CPCC21D9/50
Inventor 邓建军李杰陈起龙杰庞辉勇吕建会张亚丽任鑫磊刘彦强陈振业张启远谢向东
Owner WUYANG IRON & STEEL
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