3322Carbon Steel Castings

3322.1SCOPE

Provide mild to medium strength carbon steel castings for general applications requiring a tensile strength of no more than 70,000 psi.

3322.2REQUIREMENTS

Provide carbon steel castings meeting the requirements of ASTM A27, Standard Specification for Steel Castings, Carbon, for General Application, for the grade required by the Contract and this section. A Grade Designations If the Contract does not specify a strength grade, provide castings in accordance with the requirements for ASTM A27, Standard Specification for Steel Castings, Carbon, for General Application, Grade 70-36. Supply castings in a normalized or normalized and tempered condition. B Casting Details Provide casting patterns that will produce a finished casting with the dimensions and details shown on the Plans. Provide draft by increasing the net dimensions without reducing the metal thickness as required by the Contract. Boldly fillet sharp angles. Provide fillets of a size that does not reduce the clearance required by the Contract. Round external corners on castings, except ornamental types, to a radius of 3/16 inch. Make allowance for shrinkage and provide enough Material on surfaces requiring a finish to produce castings of the specified size and shape after the completion of finishing operations as shown on the Plans. The Engineer will not allow split cores between unfinished surfaces of restricted clearance. Provide face cores of one piece, unless castings require machine finishing. Provide chaplets spaced, and in numbers to prevent the chaplets from impairing the strength of the casting . Provide chaplets that are completely fused. Fabricate castings using methods that will ensure corners, arises, and edges are completely filled . For castings with one machine surface, cast with the machine surface down. Do not use metal from different melts in the same casting. Do not withdraw castings from the mold until properly cooled. Do not quench castings to speed up cooling. C Workmanship and Finish The Engineer will reject castings with structural defects in a casting, including blow hole shrink pipes, sand hole cracks, checks, slag inclusions, cold shuts, unfilled arises, warped surfaces, or deformation from core or flask movement. Do not repair castings with minor defects until the Engineer provides permission and approves the repair method. Grind extensions, high spots, and rough edges resulting from pouring connections, smooth and flush with the casting surface. Clean castings of foundry sand, rust, scale, and other deleterious Material before painting, galvanizing, or metalizing as required by the Contract. Clean, paint, galvanize, and metalize castings in accordance with 2471, “Structural Metals.”

3322.3SAMPLING AND TESTING

If the Engineer suspects the soundness of a casting, the Engineer has the right to subject castings to radiographic or magnetic particle inspection, at no additional cost to the Department. A Test Specimens Attach test coupons using the preferred method of a keel block, but do not make attachments that may structurally weaken the casting. Cast 2 test coupons integrally for each casting greater than 750 pounds. Provide 2 test coupons for each casting heat less than 750 pounds, and cast the test coupons as ribs, integrally and below a special block no less than 6 inches by 6 inches by 2 inches. B Foundry Control Identify castings with embossed markings, indicating the heat from which the casting was poured, together with the Bridge and piece numbers. Die mark the same information on the representative test coupons. Mark test coupons and castings for each heat. Do not remove coupons until after the castings are heat-treated. The Engineer will reject castings without proper identification unless the I nspector can identify corresponding test coupons by matching fractures.