(1) Clean the parts to be welded first, then use the wet mud to keep the traces around.
(2) Select a welding rod with a diameter of 2.5mm, adjust the current of the welding machine to 120A, and adopt a straight line method to smoothly apply welding.
(3) After all the welding is completed, the mud and slag are removed, and the rough boring is performed along the circumference of the piston rod to maintain a machining allowance of 0.1-0.2 mm.
(4) A cylinder with an outer diameter of 185 mm, an inner diameter of 125 mm and a length of 150 mm is sawed along the axis (one outer diameter of the piston rod is 125 mm), one is a rough mold, and the other is a fine mold.
(5) Apply a thin layer of red ink on the inner wall of the rough mold, then press the rough mold against the part to be repaired of the piston rod to reciprocate several times along the axis, and then use the fine boring to make the heavy red mark on the piston rod. Get rid of it. This is repeated repairs, leaving a machining allowance of 0.04-0.07mm.
(6) The piston rod is then ground to a specified size by using a 320-mesh sand slag kerosene in combination with a precision mold.
(7) Finally, hand-polished with kerosene on the back of the abrasive cloth. After measurement, the maximum error is only 0.03mm.