Cracking-resistant TP304-stainless-steel heat exchange tube of high-pressure heater

Abstract

A cracking-resistant TP304-stainless-steel heat exchange tube of a high-pressure heater is characterized in that the wall thickness of a tube is calculated according to a formula (as shown in figures); in the formula, the t, by inch, represents the wall thickness of the tube before being bent, the d, by inch, represents the outer diameter of the tube, the p, by pascal, represents the design pressure, the R, by inch, represents the bending radius of the central axis of the tube, and the S, by pascal, represents the permissible design stress. The cracking-resistant TP304-stainless-steel heat exchange tube has the advantages that residual stress generated in conventional cold rolling is eliminated so that the detection requirement of low residual stress is met, the internal surface defects are eliminated so that the special requirement for surface cleanliness is met, and further, special eddy current detection requirement, severe tolerance requirement and high-speed ultrasonic testing requirement are all met, and the heat exchange tube is less prone to cracking during running and is high in erosion corrosion resistance as compared with carbon-steel made heat exchange tubes.

Description

technical field [0001] The invention relates to an austenitic stainless steel heat exchange tube used for fresh water cooling and a high-pressure heater of a unit above a supercritical parameter, especially the heat exchange tube using TP304, TP304L, and TP304N austenitic stainless steel materials. Background technique [0002] At present, domestic high-pressure heaters and heat exchange tube manufacturers generally use carbon steel or low alloy steel for heat exchange tubes in the high-pressure manufacturing process. High-pressure heaters and heat exchange tubes made of carbon steel are not resistant to erosion and corrosion. During operation, the wall of the tube is often thinned due to fluid erosion, resulting in leakage. According to statistics, the service life of heat exchange tubes made of carbon steel is 10 years. The service life of stainless steel heat exchange tubes can reach about 25 to 30 years. Some owners and some domestic high-end manufacturers try to choose...

AI Technical Summary

Problems solved by technology

High-pressure heaters and heat exchange tubes made of carbon steel are not resistant to erosion and corrosion. During operation, the wall of the tube is often thinned due to fluid erosion, resulting in leakage. According to statistics, the service life of heat exchange tubes made of carbon steel is 10 years. about, and the service life of stainless steel heat exchange tubes can reach about 25 to 30 years

Some owners and some domestic high-end manufacturers try to choose stainless steel seamless heat exchange tubes based on the erosion resistance of stainless steel materials. However, due to the technical capabilities, manufacturing levels and manufacturing costs of domestic stainless steel heat exchange tube manufacturers, this There are many defects in seamless stainless steel heat exchange tubes: 1. This kind of seamless tube needs to be perforated in the material. The specific method is to distribute through high temperature (extrusion), or tear one inside (rotary melting perforation), these two operations It will bring many internal surface defects, such as cracks, slag inclusions, rust, scratches, depressions and internal uncleanliness

2. Due to this extrusion process, there will be serious residual stress in the heat exchange tube, which will cause stress fatigue corrosion and stress corrosion cracking under the conditions of load change, fluid impact and vibration during subsequent operation

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