Annual production of the virtues of Industry China National Standard (GB) United States ASTN (ASME) standards, DIN, JIS standard and the British Standard BS seamless steel tubes, specifically low-pressure boiler pipe, high pressure boiler pipe, seamless ship steel pipe, oil cracking pipe, high pressure chemical fertilizer equipment, seamless steel pipe, tubing and casing pipe, line pipe, hollow rod, ordinary fluid pipe, structural tubes and other small-diameter steel pipe imports HM pipe, product variety, complete specifications, widely used in petroleum, chemical, power, boilers, ships, machinery and other industries, has been sold throughout the country. Many products have been exported to the Middle East and large diameter pipe model aircraft, India, Southeast Asia and Europe and embrittlement brittle tempering temperature range based on precision tubes, can be divided into low and high temperature temper brittleness temper brittleness. After tempering brittleness precision tubes quenched martensite steel at a temperature range of 250 ~ 400 ℃ and tempered steel embrittlement, toughness of a brittle transition temperature significantly increased. Embrittlement has been precision tubes can not be reused tempering heating method to eliminate, it is also known% 26ldquo; irreversible temper brittleness% 26rdquo ;. It occurs mainly in steel alloy structural steel and low alloy high strength precision tubes. Precision has brittle fracture is intergranular tube or intergranular fracture and quasi-cleavage fracture mix. Produce tempering brittleness reason HM pipe prices, generally considered: (1) the cementite during tempering to flake in the prior austenite grain boundaries, resulting in the grain boundary embrittlement are closely related. (2) impurity elements such as phosphorus in the prior austenite grain boundary segregation is also one of the reasons for tempering brittleness. Phosphorus-containing less than 0.005% high purity precision tubes do not produce tempering brittleness. Austenite grain boundary phosphorus occurs when the fire heated segregation, after quenching preserved. Phosphorus in the prior austenite grain boundary segregation and cementite during tempering in the original austenite grain boundaries, these two factors cause intergranular brittle fracture model aircraft tubes, led tempering brittleness occurs. Precision Tube alloying elements have a greater impact on the tempering brittleness. Chromium and manganese promote segregation of impurity elements such as phosphorus in the austenite grain boundaries, thus contributing to tempering brittleness, tungsten and vanadium virtually no impact on the toughness of a molybdenum reduces brittleness transition temperature tempering precision tubes, but not enough suppression tempering brittleness. When the silicon can be postponed tempered cementite precipitation, temperature increase its generation, it can improve the precision tubes tempering temperature brittleness occurred. Large-diameter pipe model aircraft, model aircraft pipes, pipe industry by virtue virtue Liaocheng Industry Co., Ltd. Liaocheng virtue Pipe Co., Ltd. (www.meidegc.com) (www.meidegc.com) (www.mdwfg.com) (www.mdggc.com) strong, credible, Liaocheng in Shandong steel industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead virtue of Industry and you work into the brilliant, for a better future!