Cold-drawn seamless steel pipes are used in precision mechanical structures, hydraulic equipment and good surface treatment for cold-drawn or cold-rolled precision seamless pipes. High precision wire drawing, strict diameter and dimension accuracy (tolerance), external surface smoothness, roundness, flatness, good uniformity of thickness.

Heat treatment of cold-drawn seamless steel pipe:
(1) Cold-drawn steel annealing: refers to the process of heating the metal material to the appropriate temperature, holding a certain time, and then slowly cooling the heat treatment process. Common annealing processes include recrystallization annealing, stress relief, spheroidization annealing, complete annealing and so on.  The purpose of annealing is mainly to reduce the hardness of metal materials, improve plasticity, cut Harix pressure processing, reduce residual stress, improve the homogeneity of structure and composition, and can be heat treated or prepared.

(2) Ordinary cold-drawn steel: refers to steel or steel AC3 or ACM heating (critical temperature of steel) more than 30-50 degrees C, maintain the appropriate time of air-cooled heat treatment process. The purpose of normalizing is to improve the mechanical properties, processing properties, grain refinement, elimination of structural defects, preparation for heat treatment and after structure of low carbon steel.


(3) Quenching of cold drawn steel: heating at a temperature higher than Ac3 or Ac1 (the lower critical temperature of steel) and then cooling at an appropriate rate to obtain martensite (or shell heat-treated structure). Common salt bath quenching process quenching, martensite quenching, surface quenching and partial quenching isothermal quenching. The purpose of quenching is to obtain martensitic steel in order to improve the hardness, strength and wear resistance of the workpiece, prepare and heat treatment after organization.




(4) Tempering of cold drawn steel: quenched steel, then heated to the temperature below Ac1, heated for a certain time, then cooled to room temperature for heat treatment. Tempering common grinding, tempering, tempering and repeated grinding. The purpose of tempering is to eliminate the stress produced by quenched steel, which has high hardness, wear resistance, plasticity and toughness.




(5) Cold-drawn steel quenching: refers to heat treatment quenching and tempering of steel or composite steel. Used for quenching and tempering steel. Generally refers to the carbon structure of carbon steel and alloy steel.




(6) Chemical treatment of cold-drawn steel: refers to the heat treatment of metal or alloy workpieces in a constant temperature medium, one or several elements are put on its surface, changing its chemical composition, microstructure and heat treatment process performance. Common chemical heat treatment processes are: carburizing, nitriding, carbonitriding, aluminizing infiltration. The purpose of chemical treatment is to improve the surface hardness, wear resistance, corrosion resistance, fatigue resistance and oxidation resistance of steel.




(7) Cold-drawn molten steel processing: the alloy is heated to the high temperature single-phase zone, keeping constant temperature, so that the phase is completely dissolved, rapidly dissolved into solid solution, and the supersaturated solid solution heat treatment process is obtained. The purpose of solution treatment is mainly to improve the toughness and toughness of steel and to prepare precipitation hardening alloys.