Method for repairing break of universal connecting rod of universal coupling

A method for repairing break of a universal connecting rod of a universal coupling, comprising steps of:

• 1) cleaning and detecting cracks, for identifying damage degrees of different parts of the universal connecting rod of the universal coupling;
• wherein the step 1) specifically comprises steps of:
• a:
• cleaning surface greasy dirt, a rust layer, a fatigue layer and irregular cracks, combining colored crack detection and ultrasound crack detection for ensuring base cracks are completely detected and an accurate detection result is obtained;
• wherein no potential defects are neglected;
• b:
• if the cracks exist at a joint of an axle end of the universal connecting rod and a body axle, where a shear stress is most concentrated, eliminating by turning;
• specifically, defining the crack as a center line, turning a U-shaped groove which is evenly distributed at both sides of the center line with a turning tool;
• turning at two faces of the universal connecting rod in such a manner that an upper portion and an lower portion of the groove form a shape of ;
• adding cooling liquid during turning for cooling, so as to strictly control an axle temperature at 40-50° C.;
• c:
• combining the colored crack detection and the ultrasound crack detection for detecting, so as to ensure that base defects are completely eliminated;
• d:
• coarsening:
• cleaning a greasy dirt layer, turning the fatigue layer for 5-10 mm, then identifying whether a crack defect exists or not by the ultrasound crack detection;
• and
• e:
• purifying:
• removing fragments and residues on metal surfaces of a component to be repaired with NaOH, Na2CO3 and NaNO3;
• 2) providing primary anneal:
• sampling for detecting a chemical element ingredient of a base, and identifying proportions of different chemical elements in the base;
• calculating a coefficient of expansion, and setting overall temperature increase and decrease time and speed of the universal coupling, putting into an ion radiation furnace, and providing gradient heating;
• 3) forming gradient in an order of a bonding layer, a transition layer, a working layer and a processing layer, preparing depositing alloys with an immerse-melting method;
• depositing layer by layer with a high-power welding machine and a special welding stick, in such a manner that 43% of the depositing alloys infiltrate into 57% of a base metal according to a depositing layer requirement until a certain redundancy is reached;
• 4) providing secondary anneal:
• after a depositing layer reaches the certain redundancy, putting into the ion radiation furnace again;
• according to a design requirement, controlling a temperature during a whole process, keeping the temperature and then providing gradient cooling as well as eliminating a welding stress, for avoiding too much contrast of an overall temperature of the base which forms a new stress construction point and thus generates new potential break;
• after reaching a design temperature, taking out of the ion radiation furnace and cooling to a room temperature;
• 5) firstly milling a peak of the depositing layer with a manual milling method, then machining and mechanically milling a repaired portion, so as to ensure that a repaired surface satisfies size and performance requirements of a blueprint;
• and
• 6) controlling a quality:
• through appearance analysis and comparison, size detection, hardness comparison before and after repairing, chemical element detection of a depositing area and the base, the ultrasound crack detection, and magnetic powder crack detection, ensuring the quality of overall repairing.