Seven major steel production processes (too complete)-3

SBS Steel Structure C. correction and forming 1) Correction (1) Finished cold correction, the general use of flange straightening machine, straight machine, hydraulic machine, press and other mechanical force to correct. (2) Flame correction, heating method a little bit of heating, linear heating and triangular heating three. ① low-carbon steel and ordinary low-alloy steel heat correction heating temperature is generally 600 ~ 900 ℃, and 800 ~ 900 ℃ for the thermoplastic deformation of the ideal temperature, but not allowed to exceed 900 ℃. ② in the carbon steel will be due to deformation and cracks, so the carbon steel generally do not have flame correction. ③ ordinary low-alloy steel after heating should be slow cooling. ④ process 2) Forming (1) Thermal processing: The low-carbon steel are generally in the 1000 ~ 1100 ℃, the thermal termination temperature should not be less than 700 ℃ Heating temperature 500 ~ 550 ℃ steel brittle, hammering and bending is strictly prohibited, or easy to break steel. (2) Cold processing: steel at room temperature for processing production, most of the use of mechanical equipment and special tools for. D. edge machining (including end plane) 1) Commonly used edge processing methods are: shovel edge, planning edge, milling edge, carbon arc gouging, gas cutting and groove machining. 2) Gas cutting parts, when the need to eliminate the affected area for edge processing, the minimum processing margin of 2.0 mm. 3) The depth of the machining edge should be able to ensure that the surface defects removed, but not less than 2.0 mm, after processing the surface should not have damage and cracks in the grinding wheel processing, grinding traces should be along the edge. 4) Carbon structural steel parts of the edge, after hand cutting, the surface should be cleaned, cannot have more than 1.0 mm roughness. 5) The end support of the component requires a flat top and a high cross-section accuracy of the component, and no matter what method is cut and what kind of steel is used, it must be trimmed or trimmed. 6) Construction drawings have special requirements or requirements for the edge of the welding need to plan side, the general plate or steel cutting edge without planning. 7) The edge of the parts for mechanical automatic cutting and air arc cutting, the cutting surface flatness, cannot exceed 1.0 mm. The main edge of the main force components, after the gas cutting need to plan side or milling edge of the processing margin, each side of at least 2 mm should be no glitches and other defects. 8) column end milling after the top contact surface should be more than 75% of the area close to the use of 0.3 mm feeler inspection, the plug into the area of not more than 25%, the edge of the gap should not be greater than 0.5mm or so. 9) The choice of milling and milling should be based on the work piece material and processing requirements to decide, a reasonable choice is the quality of processing assurance. 10) The end of the part of the processing should be carried out after the correction. 11) Should take the necessary measures in accordance with the form of components to ensure that the milling side and the axis perpendicular. E. made of holes 1) High-strength bolts (large hexagon head bolts, torsional shear bolts, etc.) used in the components, etc., for the production of holes such as tapping screws, etc., drilling, milling, punching, reaming or countersinking The 2) The component hole is preferentially used for drilling, when it is proved that some material quality, thickness and aperture, punching does not cause brittleness to allow punching. Thickness of 5 mm below all the ordinary structural steel to allow punching, the secondary structure thickness of less than 12 mm allows the use of punching. In the punching hole, shall not be followed by welding (groove), unless the material after punching, still retain a considerable toughness, then welding construction. In general, when the hole is needed to drill, the punching hole must be 3 mm smaller than the specified diameter. 3) Before drilling, one is to wear a drill bit, the second is to reasonably choose the chip margin. 4) made of bolt holes, should be cylindrical, and perpendicular to the location of the steel surface, the slope should be less than 1/20, the hole should be no burr, rupture, flare or bump traces, cutting should be cleared clean. 5) Refined or hinged bolt hole diameter and bolt rod diameter equal to the use of drilling or assembly after reaming, holes should have H12 accuracy, hole wall surface roughness Ra ≤ 12.5μm.

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