40cr SMLS Pipe Composition and Role

Sep 15 13:08 2017 Marine Lee Print This Article

40cr smls pipe production methods can be hot-rolled, hot extrusion, cold rolling and cold drawing. In recent years, due to the continuous casting and rolling technology and a variety of new welding technology and non-destructive testing technology applications, 40cr smls pipe quality continues to improve, in the use of all parts of the replacement of 40cr smls pipe, The price is about 20% lower than the seamless tube. 

The current industrial applications of 40cr smls pipe in the pipe and seamless tube each 50%.

First,Guest Posting the high temperature plasticity of the 40cr seamless steel pipe is related to the residual α phase. The general plasticity decreases with increasing α phase. In addition to the alpha phase, there are other residual phases in the austenitic 40cr seamless steel tubes, such as various forms of carbides, intermetallic compounds and the like. The excess of the relative 40cr seamless steel pipe has an impact on the degree of impact depends on their number and status. The excess phase is heated at the grain boundary, which will significantly deteriorate the plasticity of the metal. Austenitic 40cr seamless steel pipe under low temperature plasticity, deformation resistance (see metal deformation resistance) large, the use of inclined rolling perforation (see two roll inclined rolling perforation) should pay special attention to select reasonable deformation parameters and temperature parameters. Austenitic 40cr seamless steel pipe after solid solution treatment (often used after rolling heat quenching water) after the single-phase austenite, which is characterized by high σb, but σs low, elongation and toughness are large, cold deformation Good performance, it is desirable to take a large amount of deformation. But the cold deformation of the processing of hardening, so continue to poor processing performance.

Second, so oblique rolling perforation should pay attention to control the lateral deformation, should take a smaller degree of oval. Cold and hot-rolled tube of the hole oval to be larger, and should take a small amount of deformation, so as not to ears, etc., in the tension-free reduction (see the tube without tension reduction) 40cr seamless pipe thickening, while the reduction of the hole type of oval to take some larger. 40cr seamless steel pipe production characteristics plasticity. Marble 40cr seamless steel pipe at high temperature for a single austenite when the perforation is not difficult, but when there is biphase tissue perforation performance is reduced. Tube heating temperature is generally 1130 ~ 1160  (center temperature), the furnace temperature should be less than 900 , finishing temperature should be higher than the critical point transition temperature, low carbon is not less than 850 , high carbon does not exceed 925 . Marble 40cr seamless steel pipe with the increase in carbon content, steel strength and hardness, plasticity reduction, cold drawing should be used when the liner rod pull, easy to burst after the air.

Third, the ferrite 40cr seamless steel pipe is a single phase structure, there is no critical transition point (phase change), so the tube heating time is long and the temperature is high when the grain grows seriously, resulting in steel plasticity decreased significantly. The maximum temperature of the tube heating is 1000 ~ 1060 . In this temperature range the steel has good plasticity (perforation performance). Cold-drawn hammer before the heating temperature of 700 ~ 850 , heating to prevent carburizing, hammer after the water quenching. As the ferrite chromium 40cr seamless steel pipe with room temperature brittleness, cold processing performance is poor, easy to crack at the time of cold cracking and pull off, it is best in a certain temperature conditions under the pull (see pipe temperature pull), pull speed is not appropriate is too big. Cold rolled ferritic 40cr seamless steel pipe, the pipe rolling deformation when the degree of not more than 40% to 48%. In the later pass (after surface preparation and heat treatment), according to the degree of grain refinement, the degree of deformation can be increased to 55% '~ 65%. In order to avoid cracking of the steel pipe during rolling, the temperature rise of the tube during rolling is advantageous, and therefore, in most cases, the steel is cooled without cooling the tool and metal.

Usually known as resistance to atmospheric, steam and water and other corrosive media corrosion of steel, said acid, alkali, salt and other chemical corrosion medium corrosion of steel for the acid-resistant steel. 40cr seamless steel and acid-resistant steel is a general term is rust-resistant steel. Chromium is the main alloying elements, in addition to often add nickel, molybdenum, titanium, niobium, molybdenum and so on. 

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Marine Lee
Marine Lee

40cr SMLS Pipe Composition and Role

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