1. Phenomenal from welding line or state of thick any crystalline substance can see on the close fracture surface that seam an area () laying a plan. 2. of case study (1) warm-up is beyond the mark, solder mouth reachs his to seam area metal nearly intense be affected by the heat. (The contact when 2) warm-up is too light, intermittent time is too short, quantity of heat is centered overly at solder mouth. (The region of thermal treatment zone with 3) edge fore-and-aft weldment is too wide, upset allowance slants small, upset process can't make the plasticity with the close proper generation that seam an area is out of shape, fail to eliminate overheat metal at solder mouth besides. (4) for upset save labour, electrified upset continuance is longer, or upset is not gotten law, cause metallic overheat. 3. of of measure of prevention and cure (1) determines its warm-up rate according to the circumstance such as level of reinforcing steel bar, breed and norms, and aborning is severe impose control. Master to facilitate, appropriate adopts warm-up allowance and the measure that warm-up frequency photograph combines. Warm-up allowance should be 1 ～ 2mm, warm-up frequency is 1 ～ 4 times, pass warm-up allowance, the rear sight finger on welder of have the aid of, accurate control warm-up is initiative time; Through noting number, but the stopping time of timely control warm-up. (2) takes kind of low frequency warm-up, control the osculatory time of warm-up, intermittent time and thrust appropriately, make contact place can obtain wider microtherm thermal treatment zone already, improve the performance when contact, do not send the overheat area with large generation again. (3) controls the temperature when upset and allowance strictly. When warm-up temperature on the high side, can accelerate the rate of whole cremate process, can place afresh when necessary hold reinforcing steel bar to have fast cremate process again, need to ensure at the same time its upset allowance, so that upset process can be below strong case,finish. Eliminate overheat metal effectively thereby. (4) controls electrified upset process strictly. Soldering when the reinforcing steel bar with larger section, if be not worth because of handlers physical strength, can increase assistant to cooperate with upset, avoid by all means uses the harmful method that prolongs electrified upset process. CNC MillingCNC Machining