The tolerances set forth herein represent what the Forging Industry Association believes to be typical within the industry, as determined by actual measurements . Is Die Steel Forging Standard – Download as PDF File .pdf), Text File .txt) or read IS to 3 (): Tolerances for Closed Die Steel. Resource for typical forging tolerances with impression die forgings.

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Match Tolerances are based on weight of the forging after trimming and are expressed as decimal inch or decimal millimeters according to Table III, below. Radii Tolerances relate to all fillet radii and corner radii.

Largest Diameter mm x Die Wear Tolerance factor.

Surface Tolerances relate to depth of dressouts, scale pits and other imperfections on the surface of forgings. Greatest Length x Die Wear Tolerance factor. The male portions of dies may, in special situations, tend to mushroom or upset rather than wear. Minimum Finish Stock Per Surface.

The Tolerance on flat portion is computed first: Tolerances in this publication are expressed in decimal inch with metric equivalents sometimes referred to as “soft” metric conversion in the belief that this represents a practice most common in the industry at the time of publication. Block-type forgings with neither length, width. If draft is removed as result of trimming, broaching or punching, the minus radius tolerance The purchaser should indicate his first operation locating points, normally a part of the drawing, and give prior notice should these points be changed.


Straightness Tolerances are applied independently of, and in addition to, all other tolerances. Over to x Be sure to contact technical personnel at your forging source for help in determining such special capabilities. Match Tolerances are expressed as decimal millimeter in units of 0. In cases where measurements for determining match tolerances must be made from surfaces of the forging where uneven wearing of the dies has caused surplus stock, accuracy depends on making the proper allowances for these wear-caused surpluses, and eliminating their influence from the computation.

Diameter mm x Die Wear Tolerance factor. Over to incl.

There are practical limitations in dimensions and other characteristics of forged 33469 or products which vary tolerqnce to the part or product and the producer’s equipment.

Decimals used in computing tolerances are totaled and raided to the next highest 0. The Protrusion is checked against a line perpendicular to the plane established for checking the flat portion: Forging dimensions are commonly analyzed independently, with consideration given to all applicable tolerances including match, straightness, length and width but not including die wear. Tolerance on Length Dimension.

Flash Extension Tolerances are based on weight of the forging after trimming, and related to the amount of flash extension. Extremity Tolerances relate to variations in height of protrusions steps which are perpendicular to the fundamental parting line and are independent of die closure, die wear and other factors dealt with in this book. Flat and thin with protrusion at right angles to the parting line. Tolerance on Internal Dimension. Length x Die Wear Tolerance factor. See examples 7 and 8. See Table II, below.

The minimum should be plus or minus 0.


9. APPENDIX A – TOLERANCES FOR IMPRESSION DIE | Forging Industry Association

These include, cold and forgijg coining to achieve closer thickness tolerances, using special pressure padded trimmers for improving straightness, cold sizing of holes for improved tolerances on hot pierced holes, and warm forging as a manufacturing process. Over Over 0. Straightness Tolerance applied to flat portion. This tolerance applies only to steps that are contained in one die.

IS 3469-1 to 3: Tolerances for Closed Die Steel Forgings

Weights of Forgings after Trimming, in Pounds. The following procedures will apply concerning dimensioning on forging drawings: Over 50 tlerance incl. Die Wear Tolerances do not apply on center-to-center dimensions.

The degree of precision attainable in the manufacture of forged parts or products is dictated by the essential forginb of forging equipment and unavoidable contingencies in forging operations. The Straightness Tolerance on a protrusion is 0. This will assist in the design of forging dies and tools, and in establishing effective inspection procedures. Area at the Trim Line Flash not included, expressed in square millimeters. The experience of producers and purchasers of forged parts and products indicates that the tolerances set forth herein will provide adequate dimensional accuracy for most applications.

Length mm x Die Wear Tolerance factor. Die Closure Tolerances are expressed decimal millimeter in units of 0. Radii Tolerances are expressed as decimal millimeter in units of 0.