What is a line pipe?Pipeline: oil, gas or water pumped out of the ground is sent to oil and natural gas industry enterprises through pipeline.The pipe pipe includes seamless pipe and welded pipe. The pipe end has flat end, threaded end and socket end.The connection method is end welding, coupling connection, socket connection and so on.
Application: used for transporting gas, water and oil in petroleum and natural gas industry API SPEC 5l-2011 (pipeline specification), compiled and published by the American petroleum institute, is used worldwide.The main materials of the tube are L245, L290, L360, L415, L480, gr.b, X42, X46, X56, X65, X70, X80, X100 and other steel grades.
Type of pipe tempering?According to the different performance requirements of pipeline steel tubes and the different tempering temperatures, the tempering can be divided into the following types:
1. Low-temperature tempering (150-250 degrees)
The microstructure obtained by tempering at low temperature is tempered martensite.Its purpose is to maintain the high hardness and high wear resistance of hardened steel under the premise of reducing its quenching stress and brittleness, so as to avoid the use of crack or premature damage.It is mainly used for a variety of high carbon cutting tools, measuring tools, GB/T9711.1 pipe pipe, rolling bearings and carburized parts, etc., temper hardness is generally hrc58-64.
2. Moderate tempering (250-500 degrees)
The structure obtained by moderate tempering was tempered troostite.The aim is to obtain high yield strength, elastic limit and high toughness.Therefore, it is mainly used for the treatment of various GB/T9711.1 pipeline steel pipes and hot working dies, and the hardness after tempering is generally hrc35-50.
3. High temperature tempering (500-650 degrees)
The structure obtained by high temperature tempering is tempered sorbite.Traditionally, the heat treatment combining quenching and high temperature tempering is called quenching and tempering treatment, and its purpose is to obtain better comprehensive mechanical properties such as strength, hardness, plasticity and toughness.Therefore, it is widely used in automobile, GB/T9711.1 pipeline steel pipe, machine tool and other important structural parts, such as connecting rod, bolt, gear and shaft.The hardness after tempering is generally HB200-330.