300 eries seamless pipe 08x18h10t astm a312 tp321 tp304/304l/304h 08x18h10t astm a312 tp321 tp304/304l/304h all specifications
SCH140,SCH160,XXS,DIN, JIS standard thickness
ASTM A53, A106, API 5L, ASME B36.10M-1996
DIN1626, DIN1629, DIN17175, DIN 2448
JIS G3452,JIS G3454,JIS G3455,JIS G3456,JIS G3457,JIS G3461
Q235, 20#, Q345
A53B, A106B, API 5L B,X42,X46,X52,X60, X65
Black painting, varnish paint, anti rust oil, hot galvanized, cold galvanized, 3PE,etc.
Threaded beveled ,plain ,groove
ISO9001, SGS,BV, etc
5000 TONS /month
Seamless Steel Pipe(SMLS) is made from a solid round steel billet which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube. The seamless pipe is then finished to dimensional and wall thickness specifications in sizes from 1/8'' to 36'' OD.
Models of steel pipes
Models of steel pipes
Heat treatment defect of carbon steel tube and its prevention
The heat treatment of metal materials is divided into integral heat treatment, surface heat treatment and chemical heat treatment.The heat treatment of carbon steel tube generally adopts integral heat treatment.Generally, they go through the basic processes of heating, heat preservation and cooling, all of which may produce defects.
Heat treatment process characteristics of carbon steel tube:
The first process is heating: heating under the critical point Ac1 or Ac3;The other is the heating above the critical point Ac1 or Ac3.The first is mainly to stabilize the structure of steel and eliminate the residual stress of carbon steel pipe, the second is mainly to austenitize steel.
The second process is heat preservation: The purpose is to evenly heat The temperature of carbon steel pipe, in order to get a reasonable heating structure.
The third process is cooling:The cooling process is the key process for the heat treatment of carbon steel tubes.Which determines the metallographic structure and mechanical properties of carbon steel tubes after cooling.The cooling methods of carbon steel tube used in the actual production areVarious.Frequently used cooling methods are furnace cooling, air cooling, oil cooling, polymer cooling, water cooling.
Annealing includes recrystallization annealing, complete annealing, isothermal annealing, spheroidization annealing and elimination of residual stress annealing.Generally, high carbon, low alloy and alloy steel carbon steel pipe needs to be annealed to reduce its hardness and strength, improve plasticity, eliminate internal stress and uneven structure, refine crystalline structure, so as to facilitate the machining of carbon steel pipe and lay the foundation for the final heat treatment of carbon steel pipe.
Tempering: generally divided into low temperature tempering (150-250 ° C), medium temperature tempering (350-500 ° C), and high temperature tempering (500-650 ° C).Improve the ductility and toughness of carbon steel pipe;Make the carbon steel pipe to obtain good comprehensive mechanical properties, reduce or eliminate the residual stress caused by the quenching of carbon steel pipe and stabilize the size of carbon steel pipe, so that the carbon steel pipe does not change in the use process.In general, air cooling is adopted for tempering. In order to prevent the re-generation of internal stress on carbon steel pipe, it should be cooled slowly.For brittle carbon steel pipe with high temperature tempering, rapid cooling, such as oil cooling, should be adopted after tempering.
Quenching: the metal material heated to austenitic Ac3 line above 30 to 50 ° C, insulation rapid cooling after a period of time to make carbon steel tube and the technological process of the martensite and bainite.After quenching, thermal stress and microstructure stress will be produced, which can be generally eliminated and improved by tempering.The combination of quenching and tempering can greatly improve the comprehensive properties of steel. Other processes include solid solution treatment and shielding gas heat treatment.