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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Is.3469.1-3.1974 Die Steel Forging Standard
Iis at the Trim Line Flash not included, expressed in square millimeters. This tolerance includes allowances for: Largest Diameter x Toleranfe Wear Tolerance factor. Over to incl. Theoretical exactness is seldom attained, and it is therefore necessary to make allowance for deviations. The following procedures will apply concerning dimensioning on forging drawings: Furthermore, unless the purchaser’s drawings or specifications direct otherwise, circular shapes are normally assumed to be figures of revolution with a center on an axis, and all circular dimensions are normally shown as diameters.
The minimum should be plus or minus 0. Straightness Tolerance applied to flat portion. Tolerance on External Dimension.
There are practical limitations in dimensions and other characteristics of forged parts or products which vary according to the part or product and the producer’s equipment. See Table II, below. It is important that forging drawing be accurate and complete. Tolerance on Length Dimension. Length mm x Die Wear Tolerance tolfrance.
Where possible, tollerance are made at areas of the forging unaffected by die wear. Normally, they are in addition to tolerances for die wear.
Decimals used in computing tolerances are totaled and raised to the next highest 0. Greatest dimension x Straightness Tolerance. Diameter x Die Wear Tolerance factor.
IS 3469-1 to 3: Tolerances for Closed Die Steel Forgings
If draft is removed as result of trimming, broaching or punching, the minus radius tolerance See examples 5 and 6. Die Wear Tolerances for all length, width and diameter dimensions over mm or 30 in. Decimals used in computing tolerances are totaled and raided to the next highest 0. Raised to the next highest 0. Giving consideration to the fact that forgings undergo dimensional changes due to cooling and because forgings are formed in most cases between two impression dies that are not precisely on the same centerline, the ANSI Y All individual tolerances apply to each and every forged part unless specifically noted otherwise.
Dressouts, scale pits and other imperfections are commonly allowed on surfaces to be finish machined forginf purchaser’s specification or drawing states otherwise.
Over 10 to 30 incl. Die Closure Tolerances relate to variations in thickness of forgings as affected by the closing of the dies and die wear, and pertain to variations in dimensions crossing the toleranve parting line. In such cases, the requirements of the forging should be confirmed by purchaser and producer in advance of production. This tolerance guide provides dimensioning and tolerancing that is considered linear and not geometric.
Be sure to contact technical personnel at your forging source for help in determining such special capabilities.
Surface Tolerances relate to depth of dressouts, scale pits and other imperfections on the surface of forgings. Die Wear Tolerances do not apply on center-to-center dimensions. Match Tolerances are expressed as decimal millimeter in units of 0.
Largest Diameter mm x Die Wear Tolerance factor.
9. APPENDIX A – TOLERANCES FOR IMPRESSION DIE | Forging Industry Association
The Tolerance on flat portion is computed first: Extremity Tolerances are expressed as decimal millimeter in units of 0. The male portions of dies may, in special situations, tend to mushroom or upset rather than wear.
Over to x Greatest Length x Die Wear Tolerance factor. Allowances for die wear occuring on dimensions measured perpendicular to the fundamental parting line of the dies are included in Die Closure Tolerances Table II. Tolerance on Internal Dimension. This tolerance gorging only to steps that are contained in one die.
Appropriate value from Table V. Block-type forgings with neither length, width. The degree of precision attainable in the manufacture of forged parts or products is dictated by the essential character of forging equipment and unavoidable contingencies in forging operations. There are several special ways of providing closer tolerances on selected dimensions on forgings with added operations.
Weights of Forgings after Trimming, in Pounds. Radii Tolerances relate to all fillet radii and corner radii.
Flash is measured from the body of the forging to the trimmed edge of the flash. These include, cold and warm 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.
Area at the Trim Line Flash not included, expressed in square inches. Over 65 to x 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 os dealt with in this book.
Forgong Tolerances are applied independently of, and in addition to, all other tolerances.