Cold drawn precision seamless steel pipe refers to processing steel plates or steel strips into various types of steel through cold drawing, cold bending, cold drawing and other cold processing at normal temperature.
It has the characteristics of no oxide layer on the inner and outer walls, no leakage under high pressure, high precision, high smoothness, no deformation in cold bending, no cracks in expansion and flattening, and anti-rust treatment on the surface. It is mainly used in mechanical structures, hydraulic equipment and automobiles. Pneumatic or hydraulic components of motorcycles, such as cylinders or oil cylinders.
(2) Cold-rolled precision seamless steel pipes can save materials, improve processing efficiency, increase material utilization, and greatly improve product quality.
(3) There are many processes, the production cycle is long, and the production efficiency is low.
(4) The cold-rolled precision seamless pipe has excellent comprehensive properties, can withstand high pressure, is cold-bent, expanded, and flattened without cracking or wrinkling, and can be used for various complex deformations and mechanical processing.
(2) Pipe material preparation, including inspection, bundling, pickling, cleaning, rinsing, neutralization, drying, lubricant application, etc.;
(3) Cold working (cold rolling or cold drawing);
(4) Finished product finishing includes finished product heat treatment, straightening, sampling, head and tail cutting, inspection (manual inspection and various flaw detection), hydraulic test, oiling, packaging, warehousing, etc.
Production precautions
(1) Clean up defects
The pipe wall thickness should be uniform and there should be few internal and external surface defects; external surface polishing and internal hole defect cleaning equipment should be equipped.
(2)Reinspection
Compared with ordinary cold-drawn steel pipes, the production of cold-drawn precision seamless pipes adds a pickling and re-inspection process for hot-rolled capillary tubes. The main purpose is to ensure that the outer surface of the capillary tubes has no defects such as folds and cracks, and to eliminate folds and serious scratches on the inner surface. , pitted and other defective hair tubes.
(3)Tools
The surface finish of the tools used in the production of cold-drawn precision seamless steel pipes is required to be above Ra0.4, the dimensional accuracy is above H3, and the hardness is required to be above HRC70.
(4) Annealing
Annealing is a very important process in the production of cold drawn pipes. The quality of annealing affects both the performance of the steel pipe and the removal of iron oxide scale. Cold drawn precision steel pipes require non-oxidation bright annealing furnace equipment.
(2) Cause lattice dislocation or phase transformation of the material to occur on the surface, which will become the starting point of local corrosion such as pitting corrosion. This phenomenon of cold-drawn seamless precision steel pipe will have direct adverse effects when the deformation reaches 20% area reduction.
(3) Cold-drawn seamless precision steel pipes will leave residual stress in the material after cold processing. The residual stress is extremely detrimental to the material's resistance to stress corrosion cracking. Any degree of cold working of cold drawn steel pipes will greatly increase the SCC sensitivity of cold drawn steel pipe materials.
(4) The degree of cold working also has a negative impact on the high-temperature durable strength of cold-drawn steel pipes. Cold-drawn seamless precision steel pipes generally have higher working temperatures or higher fracture life requirements, and the lower the degree of cold working allowed.
• EN10305-1 (E215, E235, E335) seamless cold drawn tubes
• EN10305-4 (E215, E235, E335) seamless cold drawn tubes for hydraulic and pneumatic power systems
• JIS G3445 (STKM 11A, STKM 12A/12B/12C, STKM 13A/13B/13C) carbon steel tubes for machine structural
• DIN2391 (ST35.8, ST37.2, ST52) seamless precision steel tubes
• ISO3074 steel tubes for automotive purposes specification
• GOST8734 seamless cold deformed steel tube
It has the characteristics of no oxide layer on the inner and outer walls, no leakage under high pressure, high precision, high smoothness, no deformation in cold bending, no cracks in expansion and flattening, and anti-rust treatment on the surface. It is mainly used in mechanical structures, hydraulic equipment and automobiles. Pneumatic or hydraulic components of motorcycles, such as cylinders or oil cylinders.
1.What is cold drawing process?
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.2. Characteristics of cold drawn (rolled) precision steel pipes
(1) There is no oxide layer on the inner and outer walls of the steel pipe. It can withstand high pressure without leakage. It has high dimensional accuracy, high smoothness on the outer surface, no deformation during cold bending, and no cracks when expanded and flattened. The finished product has been heat treated with an oxygen-free medium.(2) Cold-rolled precision seamless steel pipes can save materials, improve processing efficiency, increase material utilization, and greatly improve product quality.
(3) There are many processes, the production cycle is long, and the production efficiency is low.
(4) The cold-rolled precision seamless pipe has excellent comprehensive properties, can withstand high pressure, is cold-bent, expanded, and flattened without cracking or wrinkling, and can be used for various complex deformations and mechanical processing.
3. Production process of cold-rolled precision seamless tubes
(1) Pipe material supply, the pipe materials used are hot-rolled seamless steel pipe finished pipes or pipe blanks semi-finished pipes, extruded pipes and welded pipes;(2) Pipe material preparation, including inspection, bundling, pickling, cleaning, rinsing, neutralization, drying, lubricant application, etc.;
(3) Cold working (cold rolling or cold drawing);
(4) Finished product finishing includes finished product heat treatment, straightening, sampling, head and tail cutting, inspection (manual inspection and various flaw detection), hydraulic test, oiling, packaging, warehousing, etc.
Production precautions
(1) Clean up defects
The pipe wall thickness should be uniform and there should be few internal and external surface defects; external surface polishing and internal hole defect cleaning equipment should be equipped.
(2)Reinspection
Compared with ordinary cold-drawn steel pipes, the production of cold-drawn precision seamless pipes adds a pickling and re-inspection process for hot-rolled capillary tubes. The main purpose is to ensure that the outer surface of the capillary tubes has no defects such as folds and cracks, and to eliminate folds and serious scratches on the inner surface. , pitted and other defective hair tubes.
(3)Tools
The surface finish of the tools used in the production of cold-drawn precision seamless steel pipes is required to be above Ra0.4, the dimensional accuracy is above H3, and the hardness is required to be above HRC70.
(4) Annealing
Annealing is a very important process in the production of cold drawn pipes. The quality of annealing affects both the performance of the steel pipe and the removal of iron oxide scale. Cold drawn precision steel pipes require non-oxidation bright annealing furnace equipment.
4. Defects in the processing of cold drawn seamless precision steel tubes
(1) Cold-drawn seamless precision steel pipes will cause microscopic defects such as material lattice dislocations and an increase in surface roughness, and induce martensitic transformation and precipitation of carbides. For example, austenitic steel shows an increase in magnetism after cold working.(2) Cause lattice dislocation or phase transformation of the material to occur on the surface, which will become the starting point of local corrosion such as pitting corrosion. This phenomenon of cold-drawn seamless precision steel pipe will have direct adverse effects when the deformation reaches 20% area reduction.
(3) Cold-drawn seamless precision steel pipes will leave residual stress in the material after cold processing. The residual stress is extremely detrimental to the material's resistance to stress corrosion cracking. Any degree of cold working of cold drawn steel pipes will greatly increase the SCC sensitivity of cold drawn steel pipe materials.
(4) The degree of cold working also has a negative impact on the high-temperature durable strength of cold-drawn steel pipes. Cold-drawn seamless precision steel pipes generally have higher working temperatures or higher fracture life requirements, and the lower the degree of cold working allowed.
5. Standard and material
• ASTM A519 (GR.1010, 1020, 1035, 1045, 4130, 4140) Seamless carbon and alloy steel mechanical tubes• EN10305-1 (E215, E235, E335) seamless cold drawn tubes
• EN10305-4 (E215, E235, E335) seamless cold drawn tubes for hydraulic and pneumatic power systems
• JIS G3445 (STKM 11A, STKM 12A/12B/12C, STKM 13A/13B/13C) carbon steel tubes for machine structural
• DIN2391 (ST35.8, ST37.2, ST52) seamless precision steel tubes
• ISO3074 steel tubes for automotive purposes specification
• GOST8734 seamless cold deformed steel tube
