1.What is cold drawing?
Cold drawing is a processing technology of materials. For metal materials, cold drawing refers to drawing when the material is at room temperature in order to achieve a certain shape and certain mechanical properties. Compared with thermoforming, cold-drawn products have the advantages of high dimensional accuracy and good surface finish.
Hot rolling is relative to cold rolling. Cold rolling is rolling below the recrystallization temperature, while hot rolling is rolling above the recrystallization temperature. To put it simply, a piece of steel billet is heated and rolled several times, then trimmed and straightened into a steel plate. This is called hot rolling. It can significantly reduce energy consumption and reduce costs. During hot rolling, the metal has high plasticity and low deformation resistance, which greatly reduces the energy consumption of metal deformation. Hot rolling can improve the processing performance of metals and alloys, that is, break the coarse grains in the casting state, significantly heal cracks, reduce or eliminate casting defects, transform the as-cast structure into a deformed structure, and improve the processing performance of the alloy.
2.What is cold drawn seamless pipe?
Cold drawn seamless pipe is a kind of seamless pipe produced through cold drawing process. Correspondingly, seamless pipe produced through hot rolling process is called hot rolled seamless pipe.
3. Advantages and disadvantages of cold drawn seamless pipes
advantage:
(1) The molding speed is fast, the output is high, and the coating is not damaged. It can be made into a variety of cross-sectional forms to meet the needs of use conditions.
(2) Cold rolling can cause large plastic deformation of steel, thereby increasing the yield point of steel.
shortcoming:
(1) Residual stress exists in the section, which affects the overall and local buckling characteristics of the steel;
(2) The free torsional stiffness of the section is low.
(3) The wall thickness of cold-rolled steel is small and its ability to withstand localized concentrated loads is weak.
4. The difference between cold drawn seamless pipe and hot rolled seamless pipe
(1) Different uses. Cold-drawn seamless steel pipes are mainly used to manufacture pipes and mechanical parts for high-precision, high-pressure, high-temperature and special medium transportation, such as automobile drive shafts, turbine engines, high-pressure vessels, etc. Hot-rolled seamless steel pipes are mainly used to manufacture structural parts and fluid transportation pipes that do not require high strength but require good toughness, such as building structures, boilers, water and gas pipelines, etc.
(2) Different materials and properties
Cold-drawn seamless steel pipes are generally made of high carbon steel or alloy steel, which have high strength, hardness and fatigue resistance, but relatively poor toughness. Rolled seamless steel pipes are made of low carbon steel or low alloy steel, which have lower strength and hardness but better toughness and are easy to process and weld.
(3) Different production processes
Cold-drawn seamless steel pipes are made by passing a steel billet through a hole pattern with a round hole of a certain specification, and through multiple drawing and annealing treatments, the pipe diameter is gradually reduced and the pipe wall thickness is increased. Hot-rolled seamless steel pipes are made by continuously rolling the steel billet through multiple rollers at high temperatures to gradually deform and thin the steel billet, and finally form seamless steel pipes of the required specifications.
Cold drawing is a processing technology of materials. For metal materials, cold drawing refers to drawing when the material is at room temperature in order to achieve a certain shape and certain mechanical properties. Compared with thermoforming, cold-drawn products have the advantages of high dimensional accuracy and good surface finish.
Hot rolling is relative to cold rolling. Cold rolling is rolling below the recrystallization temperature, while hot rolling is rolling above the recrystallization temperature. To put it simply, a piece of steel billet is heated and rolled several times, then trimmed and straightened into a steel plate. This is called hot rolling. It can significantly reduce energy consumption and reduce costs. During hot rolling, the metal has high plasticity and low deformation resistance, which greatly reduces the energy consumption of metal deformation. Hot rolling can improve the processing performance of metals and alloys, that is, break the coarse grains in the casting state, significantly heal cracks, reduce or eliminate casting defects, transform the as-cast structure into a deformed structure, and improve the processing performance of the alloy.
2.What is cold drawn seamless pipe?
Cold drawn seamless pipe is a kind of seamless pipe produced through cold drawing process. Correspondingly, seamless pipe produced through hot rolling process is called hot rolled seamless pipe.
3. Advantages and disadvantages of cold drawn seamless pipes
advantage:
(1) The molding speed is fast, the output is high, and the coating is not damaged. It can be made into a variety of cross-sectional forms to meet the needs of use conditions.
(2) Cold rolling can cause large plastic deformation of steel, thereby increasing the yield point of steel.
shortcoming:
(1) Residual stress exists in the section, which affects the overall and local buckling characteristics of the steel;
(2) The free torsional stiffness of the section is low.
(3) The wall thickness of cold-rolled steel is small and its ability to withstand localized concentrated loads is weak.
4. The difference between cold drawn seamless pipe and hot rolled seamless pipe
(1) Different uses. Cold-drawn seamless steel pipes are mainly used to manufacture pipes and mechanical parts for high-precision, high-pressure, high-temperature and special medium transportation, such as automobile drive shafts, turbine engines, high-pressure vessels, etc. Hot-rolled seamless steel pipes are mainly used to manufacture structural parts and fluid transportation pipes that do not require high strength but require good toughness, such as building structures, boilers, water and gas pipelines, etc.
(2) Different materials and properties
Cold-drawn seamless steel pipes are generally made of high carbon steel or alloy steel, which have high strength, hardness and fatigue resistance, but relatively poor toughness. Rolled seamless steel pipes are made of low carbon steel or low alloy steel, which have lower strength and hardness but better toughness and are easy to process and weld.
(3) Different production processes
Cold-drawn seamless steel pipes are made by passing a steel billet through a hole pattern with a round hole of a certain specification, and through multiple drawing and annealing treatments, the pipe diameter is gradually reduced and the pipe wall thickness is increased. Hot-rolled seamless steel pipes are made by continuously rolling the steel billet through multiple rollers at high temperatures to gradually deform and thin the steel billet, and finally form seamless steel pipes of the required specifications.
