Large-scale connecting rod forgings are large in size, small in number and not complex in shape, and many rectangular sections. General use of hydraulic press free forging molding.
In the inspection of large-scale connecting rod forgings, it is necessary to ensure that the shape dimensions meet the requirements of forging drawings. Commonly used measures (such as rulers, calipers, dash and needle or vernier calipers, etc.) and ancillary tools (such as crossed plate, bracket, square box), and with the method of marking to check, when the number of forgings, should be a model check. The introduction of the underlined method is as follows:
① clean the surface of the connecting rod forging oxide skin, burrs and other dirt. Check the surface quality of forgings, determine the location and size of defects, and the nature of defects.
② selects the connecting rod a plane as the datum plane, uses the bracket which puts on the dash plate to support the forging, and makes the forging base plane parallel with the dash plate.
② in the surface of the forging and the side of the underlined part of the painting, is generally coated Lan or other quick-drying pigments.
④ according to the shape dimension of the connecting rod forgings, the relative elevation of the forgings on the crossed plate, calculating the plane coordinate dimensions of the connecting rods, using the crossed plate and the needle, or the line vernier caliper to draw the baseline. In the same way, the contour dimension of the connecting rod thickness direction is drawn, and the machining allowance and its division state of the forging thickness direction are approved.
⑤ use needle, ruler, adjust three point centering plate plane same with the connecting rod plane and fixed on the connecting Rod hole, draw the connecting rod Symmetrical center line and connecting rod two holes center line, guarantee hole distance dimension.
⑥ uses compasses to draw the connecting rod two head shape size, determines the rod size end size point, uses the needle and the ruler, delimits the rod part shape size, and delimits the transition arc.
⑦ approves the shape dimension of the planar outer profile of the connecting rod forgings to determine the distribution status of the machining allowance. In the process of marking, the distribution of surface defects of forgings should be taken into account and the defects should be excluded from the shape and size of the parts. If the local allowance is found to be too small, the margin method should be used to underline until the limit position is reached. The result of the line, the end still has the partial allowance partial small phenomenon, in estimates can satisfy the mechanical processing request, should indicate the allowance small part, in order to the machine processing special attention.