Precautions for Straightening High-Pressure Boiler Tubes During the Quenching Process

GB5310 20G high-pressure boiler tubes are a type of boiler tube classified under seamless steel pipes. Their manufacturing method is the same as that for seamless pipes, but the steel grades used for producing these tubes are subject to strict requirements. During service, high-pressure boiler tubes are often exposed to high temperatures and high pressure. Under the influence of high-temperature flue gas and steam, the tubes undergo oxidation and corrosion. Therefore, the steel pipes must possess high enduring strength, high resistance to oxidation and corrosion, and good microstructural stability. High-pressure boiler tubes are primarily used to manufacture superheater tubes, reheater tubes, guide tubes, and main steam pipes for high-pressure and ultra-high-pressure boilers.

During the quenching or tempering process of GB5310 high-pressure boiler tubes, the combined effect of thermal stress and transformational stress causes deformation. Utilizing phase transformation characteristics for reasonable straightening is a relatively straightforward process method that can yield favorable results.

1. Straightening While Hot
   When the steel is quenched and the GB5310 high-pressure boiler tube cools to a temperature near the Ms (martensite start) point, the austenite has not yet transformed into martensite. This method takes advantage of the good plasticity of austenite in this state for straightening.

2. Stabilization Straightening Using Residual Austenite
   This method involves straightening in a cold state, utilizing the large amount of residual austenite retained after quenching.

3. Local Rapid-Cooling Straightening
   This technique involves rapidly cooling the convex, deformed areas to cause contraction. The temperature should not fall below the Ms point to avoid initiating martensitic transformation during this operation.

4. Straightening in the Tempered State
   This approach employs specialized tempering fixtures or applies pressure for straightening during the tempering process.

Tags: Bolier Tube,  Steel Pipe for Boiler,  Steel Tube for Exchanger,  Bolier Pipe,