锻工中级考试试题（Hammerer intermediate examination）.doc

锻工中级考试试题（Hammerer intermediate examination） Hammerer intermediate examination papers (A volume) Fill in the blanks (2 cents per room, 46 points) 1, the size of the plane graphics, according to its role can be divided into fixed line size and location size of two categories. 2, for the expression of parts shape, the national standard provides view, cutaway view, section and so on. 3. When dimensioning, the following principles must be followed: correctly select the starting point of dimensioning, dimension reference, and correctly use dimensioning 4 、 there are two main types of stainless steel, chromium stainless steel and chromium nickel stainless steel. 5, large ingot internal defects are: segregation, inclusion, porosity, shrinkage hole, loose and transgranular; the external defects are cracks and splash scars 6, there are white spots not only lead to the mechanical properties of forgings declined sharply, and because the white spots of high stress concentration, heat treatment quenching will make the parts or parts used in cracking, suddenly broken, causing a crash event. Therefore, once a white spot is found, it must be scrapped 7. The microstructure, mechanical properties, thermal conductivity and shape of the steel vary during the heating process. 8. The defects that may occur during heating are oxidation, carbon removal, overheating, over burning and internal cracks. 9, metal is heated to near the melting point, low melting point material grains first began to melt, and because in the furnace gas or oxygen oxidizing gases into the material, oxide grains, forming crust in the grain around the damaged grain links between this phenomenon overfiring. 10, the quality of the general forgings can be calculated according to the nominal size of each part of the forging parts, and then the total quality is calculated. Two, the noun explanation (5 points per subject, 15 points) 1. Segregation: the inhomogeneity of chemical composition and impurity distribution in each