Is the difference between What cold rolled steel and hot rolled steel in metal stamping? Process?
usually in the stamping production, will be used in cold rolling and hot rolling steel processing products, then the cold and hot rolling steel, what is the difference? < p >, < the concept of cold and hot. Hot with the continuous < p > casting slab or slab as raw material, after reheating furnace heating. High pressure water in addition to scale into the roughing mill roughing material, cutting head, tail and, then enter the finishing mill, the implementation of the computer controlled rolling and finally after rolling through the laminar cooling (computer controlled cooling rate and roll down) coiler coiling, become straight hair volume. Head and tail hair straightener roll often forms a tongue shape and the fishtail shape, thickness Width of, poor accuracy, edge has wavy, hem tower, and other defects. Its weight is heavy, the diameter of the steel coil is 760mm. (general system industry likes to use. The hair straightener roll after cutting head, tail cutting, cutting edge and multi-step straightening straight and flat finishing line processing, cut into boards or heavy volume, that is, to become: hot rolled steel, flat steel hot rolled coil, slitting with etc. products. Hot finishing rolling by pickling descaling and oil is made by pickling hot-rolled coils. Cold < < p > 2 hot rolled steel coil as raw material, after the removal of oxide by pickling of cold rolling, the finished rolling hard volumes, due to continuous cold deformation caused by the cold work harden Ing to the volume rolling hard strength, increasing hardness, toughness and plastic index decrease, so stamping performance will deteriorate, can only be used for simple deformation of the parts. Hard roll can be used as raw material for hot dip galvanizing plant, because the hot dip galvanizing line is set to have a back line. Hard roll weight is generally in the 6~13.5 tons, steel coil diameter is 610mm. General cold rolling plate, volume shall be after continuous annealing (CAPL) or bell type annealing furnace eliminate cold hardening and rolling stress, and reach the corresponding standard mechanical performance index. The surface quality, appearance and size precision of the cold rolled steel plate are better than that of the hot roll Ed plate, and the thickness of the product is about to 0.18mm. < p > 2, cold rolling and hot rolling the advantages and disadvantages of < p > 1, hot rolling of the advantages and disadvantages: advantages: can destroy the ingot "casting microstructure, grain refinement of steel and eliminate microstructure defects, so that steel structure compact. With improved mechanical properties. This improvement is mainly reflected in along the rolling direction, so that steel is no longer a certain extent isotropic body pouring forming cracks and; bubbles, loose, but also under the action of high temperature and pressure have been welded together.
after hot rolling 1), the non metallic inclusions in the steel (mainly s Ulfide and oxide, and silicate were pressed into) thin slices, and there was a phenomenon of delamination. The performance of the steel is greatly deteriorated along the thickness direction, and it is possible to be torn between layers when the seam is contracted. Weld shrinkage induced local strain often reaches the yield point strain several times, much larger than the load induced strain; < p > 2) uneven cooling caused by the residual stress. Residual stress is in no external force under the action of internal self equilibrium stress and various section of hot-rolled steels have this kind of residual stress and general steel section size is larger, residual stress is larger. Although the residual stress is self balanced. But still have A certain influence on the steel structure under external force performance. Such as deformation, stability anti, fatigue and other aspects are likely to have a negative effect. The advantages and disadvantages of < p > 2, cold < rolling: advantages: fast molding speed, high yield, and no damage to the coating can be made varied cross-section form. In order to adapt to the conditions of use cold rolling could be to; produce steel large plastic deformation, so as to improve the yield point of the steel. < p > disadvantages: < p > 1) although in the forming process of no after thermal plastic compression, but section still exists residual stress, characteristics of the global and local buckling of the steel is bound to have an impact < p >; 2) of cold rolling steel style is generally open section, making section of free torsional stiffness is low. In bending, prone to torsion, compression is easy to occur when the flexural torsional buckling, torsional performance is poor cold formed steel < 3); wall thickness is smaller, in the plate convergence at the corner of and without thickening, bear local concentrated load capacity is weak. hot-rolled and cold-rolled < 3, difference < p > 1, cold formed steel allows for cross section appear local buckling, which can make full use of member buckling bearing capacity and hot-rolled steel does not; allow cross section the occurrence of local buckling.
hot rolling and cold rolled 2。 Steel residual stress caused by different reaso NS, so there are a lot of differences in the distribution of cross section。 Cold-formed steel section on the residual stress distribution is curved, and hot-rolled steel or welding section steel residual stress distribution is thin film type。
3 the free torsion rigidity, of the hot rolled steel is higher than that of the cold rolled steel, so the torsion resistance of the hot rolled steel is better than that of the cold rolled steel.
master the material properties of cold rolling and hot rolling, in the processing of metal stamping can better use of materials, more pressing to produce products that meet the requirements.