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Method of improving toughness of novel martensite heat-resistant steel A355P91 welding seam

An A355P91, martensite technology, applied in the field of improving the weld toughness of the new martensitic heat-resistant steel A355 P91, can solve the problems of increasing the impact toughness of the weld, reducing the surface hardness of the weld, and low impact toughness of the weld, etc. Achieve the effect of increasing impact toughness, reducing hardness, ensuring tensile strength and yield strength

Active Publication Date: 2014-03-19
ANHUI SANXING TESTING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem that the surface hardness of the new martensitic heat-resistant steel A355 P91 weld exceeds the standard and the impact toughness of the weld is low in the prior art , provides a method for improving the weld toughness of the new martensitic heat-resistant steel A355 P91, adopting the technical solution of the present invention, can achieve the purpose of reducing the surface hardness of the weld and increasing the impact toughness of the weld

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0027] A kind of method of improving the weld seam toughness of novel martensitic heat-resistant steel A355 P91 of the present embodiment, its steps are:

[0028] Step 1. Preheating before welding:

[0029] Due to the poor weldability of the new martensitic heat-resistant steel A355 P91, especially when the large-diameter weld joint is welded at room temperature or when the preheating is uneven, it is easy to produce cold cracks, so the requirements for preheating before welding are very high. Preheat the weldment of the new martensitic heat-resistant steel A355 P91. The preheating temperature range is 230°C, and the temperature is kept constant for two hours. The key point is that the specific heating program in this example is as follows: 1) at a heating rate of 3 °C / min, from room temperature to 80 °C, and keep warm for 25 minutes; 2) at a heating rate of 4 °C / min, from 80 °C to 120 °C, And keep it warm for 20 minutes; 3) Raise the temperature from 120°C to 160°C at a heat...

Embodiment 2

[0039] A method for improving the weld seam toughness of the new martensitic heat-resistant steel A355 P91 in this embodiment, the basic processing process is the same as that of Embodiment 1, the difference is that the preheating temperature in step 1 is 200°C, and the middle layer in step 2 The room temperature is controlled at 200°C. In step 4, the weldment is heated to 300°C and then kept warm. In step 5, the high temperature tempering temperature is 780°C.

Embodiment 3

[0041]A method for improving the weld seam toughness of the new martensitic heat-resistant steel A355 P91 in this embodiment, the basic processing process is the same as that of Embodiment 1, the difference is that the preheating temperature in step 1 is 250°C, and the middle layer in step 2 The room temperature is controlled at 250°C. In step 4, the weldment is heated to 350°C and then kept warm. In step 5, the high temperature tempering temperature is 770°C.

[0042] A method for improving the toughness of the weld seam of the new martensitic heat-resistant steel A355 P91 in Examples 1 to 3, by strictly controlling the temperature curve of the welding, post-heat treatment, and heat treatment processes, the tensile strength and yield strength of the weld seam are guaranteed , which reduces the hardness of the surface and increases the impact toughness of the weld. The tensile strength of the weld area is ≥585MPA, there is no crack in bending, the impact value at room temperat...

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Abstract

The invention discloses a method of improving toughness of a novel martensite heat-resistant steel A355P91 welding seam, belonging to the technical field of welding and thermal treatment. The method comprises the following steps: pre-heating a welding piece of the novel martensite heat-resistant steel A355P91 within a pre-heating temperature interval of 200 DEG C-250 DEG C, and keeping the temperature constant for two hours; controlling an interlayer temperature at 200 DEG C-250 DEG C; cooling in air to 100 DEG C-120 DEG C after welding, and keeping the temperature constant for 2 hours within the temperature of 100 DEG C-120 DEG C; carrying out post-heat treatment, heating the welding piece of the novel martensite heat-resistant steel A355P91 to 300 DEG C-350 DEG C and keeping the temperature constant for 2 hours, then naturally cooling; and carrying out thermal treatment after the post-heat treatment, wherein a high-temperature tempering temperature interval is 770 DEG C-780 DEG C. The method disclosed by the invention not only ensures tensile strength and yield strength of the welding seam, but also lowers surface hardness by strictly controlling a temperature curve in the process of welding, post-heat treatment and thermal treatment; and moreover, impact toughness of the welding seam is increased.

Description

technical field [0001] The invention relates to the technical field of welding and heat treatment, and more specifically relates to a method for improving the toughness of a weld seam of a new type of martensitic heat-resistant steel A355 P91. Background technique [0002] With the development of the electric power industry and the increasing global concern for environmental issues, saving primary energy, strengthening environmental protection, reducing harmful exhaust emissions, and reducing the global warming effect have attracted great attention at home and abroad. Improving the thermal efficiency of thermal power units and adopting supercritical and ultra-supercritical units is one of the effective ways to prevent environmental pollution. Resource-saving and environment-friendly unit is a new trend of thermal power generation equipment. [0003] In the prior art, the improvement of boiler unit parameters in large thermal power plants mainly relies on new steel materials...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/50
Inventor 吴燕陶玉安王存波
Owner ANHUI SANXING TESTING
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