Austenite stainless heat-resisting seamless steel pipe internal wall shot-blasting strengthening technique and device

Abstract

The invention relates to a shot peening strengthening method for Austenite stainless heat resistant seamless steel pipe inner wall and a device thereof. In the method, the inner wall of a steel shot of hardness more than or equal to 45HRc is shot by a spray gun under pressure more than or equal to 1.0Mpa and with high pressure gas as carrier to form a hardened layer with strengthened structure and stress, and the hardness of the hardened layer with distance 60 mum away from the steel pipe inner wall is more than 280HV or the hardness difference compared with the basal body is more than 100HV, so as to improve the resistance of the steel pipe inner against high temperature, steam, oxidation and corrosion. The device comprises a movable peening machine, a spray gun and two steel shot recovery chambers connected with the peening machine, a conveyer belt arranged below the peening machine, a steel shot elevator connected with the end of the conveyer belt, and a screener connected with the top of the conveyer belt, wherein the chamber openings of the two steel shot recovery chambers are hermitically connected with the external surfaces at the two ends of the steel pipe to form a steel shot recovery sealed chamber doubled with shot-peening function, the peening machine drives the spray gun to move along the direction of the steel pipe, and the recycling of the steel shot is realized via the steel shot recovery chambers at the two ends of the steel pipe and the conveyer belt below the steel pipe.

Description

technical field [0001] The invention relates to an austenitic stainless heat-resistant seamless steel pipe inner wall shot-peening strengthening process and its device, especially to supercritical and ultra-supercritical pressure boiler superheaters and reheaters used for thermal power generation. A shot-peening strengthening process and device for the inner wall of a rust-resistant heat-resistant seamless steel pipe to resist high-temperature steam oxidation corrosion. Background technique [0002] my country's thermal power generation has entered the era of supercritical and ultra-supercritical pressure development. The steam outlet pressure of power plant boilers has reached 28MPa, and the steam outlet temperature is as high as 605°C. Under such high parameters, 18Cr is usually used in the high temperature section of the boiler heating surface piping system. The inner wall of -8Ni type TP304H, TP321H, TP347H and other austenitic stainless heat-resistant steel pipes is faci...

AI Technical Summary

Problems solved by technology

However, there is still no processing technology or appropriate device in China that can strengthen the inner wall of austenitic stainless steel heat-resistant seamless steel pipe.

In order to realize the shot peening process of the inner wall of the steel pipe, the technology that can be used for reference is the shot peening process and equipment used to remove the scale dirt on the metal surface or the surface pretreatment before painting. layer, and can not achieve the expected anti-high temperature steam oxidation corrosion effect, specifically, it has the following defects:

[0005] 1. The air source pressure is low, P≤0.8MPa, there is not enough air source energy to shoot the inner wall of the steel pipe to form a hardened layer;

[0006] 2. The nozzle is a scattering structure, which cannot gather enough airflow energy to shoot the inner wall of the steel pipe;

[0007] 3. The spray rod is a pressure hose, which can neither ensure that the nozzle is centered 360° uniformly, nor can it ensure that the nozzle moves at a constant speed along the length direction;

[0009] 5. When operating according to the process and its device, the operator and the shot blasting studio are in the same room, and the open recycling steel shot has structural defects, so not only the steel shot cannot be fully recycled, but also the steel shot and its Dust will cause great harm to the health of operators

[0010] It can be seen that the shot blasting process and its equipment for cleaning the surface of metal materials are used to strengthen the inner wall of steel pipes, and cannot form a hardened layer that meets the main technical indicators and resists oxidation and corrosion by high-temperature steam.

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