Cold Drawn Seamless Pipe

Application and specifications (seamless):
Heat treatment of cold drawn seamless steel pipes:
(1) Cold drawn steel annealing: refers to the heat treatment process of heating a metal material to an appropriate temperature, holding it for a certain period of time, and then slowly cooling it. Common annealing processes include recrystallization annealing, stress removal, ball annealing, full annealing, etc. The purpose of annealing is mainly to reduce the hardness of metal materials, improve plasticity, or perform cutting and pressure processing to reduce residual stress, improve the uniformity of microstructure and composition. After heat treatment, microstructure preparation may be carried out.
(2) Cold drawn steel normalizing: refers to heating steel or steel to Ac3 or Acm (critical temperature of steel) above 30-50 ° C, and maintaining cooling in still air for an appropriate period of time during the heat treatment process. The purpose of normalizing is mainly to improve the mechanical properties of low-carbon steel, enhance machinability, refine grain size, eliminate structural defects, prepare for heat treatment, and then proceed with tissue preparation.
(3) Cold drawn steel quenching: refers to heating the heated steel Ac3 or Ac1 (the lower critical temperature of the steel) above a certain temperature for a certain period of time, and then obtaining martensitic (or shellfish heat treated) structure at an appropriate cooling rate. Common salt bath quenching processes include hardening quenching, martensitic quenching, isoquenching, surface quenching, and localized quenching. Quenching purpose: to improve the hardness, strength, and wear resistance of the workpiece by obtaining the steel required for martensite, and to undergo heat treatment before microstructure and preparation.
(4) Cold drawn steel tempering: After quenching the steel, it is heated to a temperature below Ac1, maintained for a certain period of time, and then cooled to room temperature for heat treatment. The common tempering processes include tempering, tempering, tempering, and multiple tempering. The purpose of tempering is mainly to eliminate the stress generated during the quenching process of steel, so that the steel has high hardness and wear resistance, as well as the required plasticity and toughness.
(5) Cold drawn steel quenching: refers to the quenching and tempering process of steel or composite steel heat treatment. Quenched and tempered steel used for quenching the steel. It generally refers to the carbon structure of carbon steel and alloy steel.
(6) Cold drawn steel chemical treatment: refers to the heat treatment process of heating a metal or alloy workpiece in a constant temperature active medium, allowing one or several elements to enter its surface, changing its chemical composition, microstructure, and properties. Common chemical heat treatment processes include carburization, nitriding, carbon nitrogen co infiltration, and aluminum boron infiltration. The purpose of chemical treatment is mainly to improve the surface hardness, wear resistance, corrosion resistance, fatigue strength, and oxidation resistance of steel.
(7) Cold drawn steel solution treatment: Heating the alloy to a high-temperature single-phase zone to maintain a constant temperature, allowing the excess phase to completely dissolve into the solid solution after rapid cooling, in order to overcome the process of supersaturation solution heat treatment. The purpose of solid solution treatment is mainly to improve the ductility and toughness of steel and alloys, and to prepare for precipitation hardening treatment, etc.
Now a phosphate coating is formed for drawing pipes, with a weight of 4-10
Seamless pipe, widely used for phosphating, with a coating weight of approximately 1.5-5 g/m ²。 These are mainly based on zinc phosphate baths operating between 50 and 75 ° C, with additives added to promote thinner coatings. Phosphating is also used for non-alloy or low alloy steel pipes with a chromium content of up to 4-6%. This coating has many advantages, all of which stem from reducing the metal to metal contact between the pipe and the mold. Therefore, cold welding damage that leads to the formation of grooves or cracks is minimized, tool and mold life is extended, and higher tensile rates can be used. The zinc phosphate coating also allows for greater reduction each time.
Surface treatment is carried out by soaking along the following route:
Alkaline degreasing.
Rinse with water.
Pickle in sulfuric acid or hydrochloric acid.
Rinse with water.
Neutralization pre flushing.
Phosphatization.
• Water flushing
Neutralization flushing.
Lubrication.
• Drying and storage.