ASTM A802-95 (R2015) pdf free download.Standard Practice for Steel Castings, Surface Acceptance Standards, Visual Examination.
1.1 This practice covers the acceptance criteria for the surface inspection of steel castings by visual examination. Four levels of acceptance standards are provided.
1.2 Acceptance levels utilize Steel Castings Research and Trade Association (SCRATA) graded reference comparators for the visual determination of surface texture, surface roughness, and surface discontinuitics described as follows:
2. 1.1.1veins, n—raised, narrow, linear ridges that form upon cracking of the sand mold or core due to expansion of sand and the resulting mold or core stresses during tilling of the mold with liquid steel.
2. 1.1.2 rat tails, n—long, narrow, linear depressions or small steps occurring on a casting surface. Rat tails form as a result of sand expansion and minor buckling of’ the mold surface during filling of the mold with liquid metal.
2.1.1.3 scab, n—a raised, rough area on a casting that usually consists of a crust of metal covering a layer of sand. Sometimes, a scab consists of a raised, rough area of essentially solid metal on the surface of a casting.
2.1.2 external chills:
2. 1 .2. 1 external chills, n—usually metal blocks, or graphite and carbon blocks, that are incorporated into the mold to locally increase the rate of heat removal during solidification. Brackets have the same purpose hut represent an integral part of the casting. Brackets are produced by providing suitable cavities in the mold or core. External chills may produce flat spots and edges (raised areas or depressions) on the casting surface. Brackets merely change the casting appearance due to their presence. Brackets may he removed or allowed to remain on the casting.
2. 1 .2.2 parting line and core print fins, n—thin projections of excess metal at the parting plane between mold halves or core and mold. Causes are improper closing of the mold, insuflicient weighting or clamping of the mold for pouring, or uneven pattern surfaces at the matching locations. Core print fins are usually caused by improper dimensions of core prints of the pattern or core box, by rough placement of cores in a soft mold, or by inadequately secured cores.
2. 1 .3 fusion discontinuities:
2. 1 .3. 1 wrinkles, n—elongated, smooth depressions of’ the casting surface, frequently appearing in closely spaced groups. Wrinkles result from irregularities of the liquid metal flow in the mold cavity, frequently associated with low temperature, and are distinguished from the more severe phenomenon of laps, folds, or cold shuts where the casting surface is actually folded over.ASTM A802 pdf download.