The latest process flow of cold drawing and grinding tube

2025-09-10 09:23:18

Cold drawn (rolled) seamless steel pipe: round billet → heating → perforation → heading → annealing → acid washing → oil coating (copper plating) → multi pass cold drawing (cold rolling) → billet → heat treatment → straightening → hydrostatic testing (flaw detection) → marking → storage.

What is Cold drawn grinding tube? Hot rolled steel pipes are made from continuous casting slabs or initial rolling slabs as raw materials, which are heated by a step heating furnace, descaling by high-pressure water, and then enter the roughing mill. The roughing material is cut into heads, tails, and then enters the finishing mill for computer-controlled rolling. After final rolling, it is cooled by laminar flow and coiled by a coiling machine to become straight coils. The head and tail of straight curls are often tongue shaped or fish tail shaped, with poor accuracy in thickness and width, and often have defects such as wavy, folded, and tower shaped edges.

Its coil weight is relatively heavy, and the inner diameter of the steel coil is 760mm. (It is commonly used in the pipe making industry.). ）After the straight coil is processed by cutting the head, tail, edge, and multiple straightening and leveling lines, it is then cut or rewound into hot-rolled steel plates, flat hot-rolled steel coils, longitudinal cutting strips, and other products. If the hot-rolled finished coil is acid washed to remove the oxide skin and coated with oil, it becomes hot-rolled acid washed plate coil. This product has a tendency to partially replace cold-rolled plates, and seamless steel pipes are moderately priced and highly favored by a wide range of users.

Cold drawn steel pipes are made from hot-rolled steel coils as raw materials, which undergo acid washing to remove oxide skin and then cold rolling. The finished product is rolled hard coils. Due to continuous cold deformation, the cold work hardening causes the strength and hardness of the rolled hard coils to increase, and the toughness and plasticity indicators to decrease. Therefore, the stamping performance will deteriorate and can only be used for parts with simple deformation. Rolled hard coils can be used as raw materials for hot-dip galvanizing plants, as hot-dip galvanizing units are equipped with annealing wires. The weight of the rolled hard coil is generally 6-13.5 tons, and the inner diameter of the steel coil is 610mm.

Generally, cold-rolled plates and coils should undergo continuous annealing (CAPL unit) or hood furnace annealing to eliminate cold work hardening and rolling stress, and meet the mechanical performance indicators specified in the corresponding standards.

The surface quality, appearance, and dimensional accuracy of cold-rolled steel plates are superior to hot-rolled plates, and their product thickness is reduced to about 0.18mm, making them highly favored by a large number of users. Deep processing of products using cold-rolled steel coils as substrates to become high value-added products.

Products such as electroplated zinc, hot-dip galvanizing, fingerprint resistant electroplated zinc, color coated steel coils and vibration reducing composite steel plates, PVC coated steel plates, etc., have excellent qualities such as beauty and high corrosion resistance, and have been widely used. Cold rolled steel coils must undergo finishing after annealing, including cutting heads, tails, edges, leveling, flattening, rewinding, or longitudinal cutting plates. Cold rolled products are widely used in industries such as automobile manufacturing, household appliances, instrument switches, construction, and office furniture. The weight of each bundle of steel plates after bundling is 3-5 tons. The weight of the flat roll is generally 3-10 tons per roll. The inner diameter of the steel coil is 610mm.