Precision steel tube is a kind of after cold drawn or hot rolling process of a kind of precision steel tube material. Because the product inside and outside wall without oxidation layer, under high pressure without leakage, high precision, high finish, cold bending deformation, flaring, flattening without cracks, etc, it is mainly used to produce pneumatic side impact door beams or hydraulic components products, such as a cylinder or cylinder, welded pipe.
Hot rolled precision tube with the slab or slab continuous casting round billet as a raw material, by step heating furnace, high pressure water descaling after entering the roughing mill, roughing expected by the cutting head, tail, and then into the finishing mill, and the implementation of computer control rolling and finishing after through laminar cooling and the winder, become straight hair volume. Straight hair volume of head and tail often show tongue shape and fish shape, thickness and width accuracy is poorer, side often exists defects such as wave shape, folding, tower. The volume weight is heavier, coil diameter is 760 mm.
To pass through the cutting head and cutting tail straight hair volume, trimming and straightening, level off of multichannel time after finishing line processing, cutting board or heavy volume, again become namely: hot rolled steel plate, flat hot-rolled coil, slitting, hot rolled precision tube, and other products. Hot rolling finishing if volume after acid pickling to remove scale and greased the hot-rolled pickling plate volumes.
Galvanized pipe folding weld process is as follows:
1, if the clearance is too large, resulting in a decrease of proximity effect, eddy heat is insufficient, the joint between the weld crystal bad and incomplete fusion or crack generation.
2, such as the gap is too small, it increases proximity effect, welding heat is too big, cause the burning of the weld; Or weld after extrusion, rolling the deep pit formation, affect the surface beam impact tubes quality of the galvanized pipe weld.
Two edges of billet heating to welding temperature, under the extrusion of squeezing roller, to form a common metal grain interpenetrate, crystallization, forming solid weld. If galvanized pipe extrusion pressure is too small, the amount of common crystal small, weld metal strength, stress produces after cracking; If the extrusion pressure is too large, will make molten metal being squeezed out of the seam, not only reduce the weld strength, and can produce a large number of inside and outside burr, may cause welding lap seam, etc.
Surface hardening
Through different heat source to heat precision steel tube, when the temperature of the workpiece surface is above the critical point for cooling, so got hardened surface layer and the core is still keeping the original tissue. More for induction heating in industrial application and flame heating surface hardening.
The chemical heat treatment
Will add heat and heat preservation impact beam tubes products placed in the medium containing active element, make the active atoms into product surface or form a compound coating, to change the surface of the organization and the chemical composition, which makes the surface of the workpiece in mechanical/physical and chemical properties.
Contact resistance heating quenching
Through electrodes will be less than 5 v voltage is added to the precision steel tube, the electrode and its current through the large contact area, and produce a lot of heat resistance, make its surface heating to the quenching temperature, then move the electrode, heat is introduced into products within the surface cooling, the purpose of quenching.
Electrolytic quenching
To place it in acid, alkali or salt aqueous electrolyte, the products meet the cathode and anode electrolyzer. After direct current electrolyte by electrolysis, release oxygen in the anode, hydrogen in precision steel pipe. Hydrogen gas film around the product, a resistance and generate heat, heat the surface to the quenching temperature, then power outages, gas film disappears, electrolyte becomes a quenching cooling medium, make its surface cooling and hardening.
Our News
