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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Extremity Tolerances are expressed as decimal millimeter in units of 0. Furthermore, unless the tollerance 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. Length mm x Die Wear Tolerance factor.
The minimum should be plus or minus 0.
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. All individual tolerances apply to each and every forged part unless specifically noted otherwise.
Diameter mm x Die Wear Tolerance factor. Die Closure Tolerances are expressed decimal millimeter in units of 0. Over to incl. Largest Diameter x Die Wear Tolerance factor. Tokerance Extension Tolerances are expressed as decimal inch, in units of 0. Tolerance on External Dimension. Flash is measured from the body of the forging to the trimmed edge of the flash.
It is important that forging drawing be accurate and complete. See forigng 5 and 6. Be sure to contact technical personnel at your forging source for help in determining such special capabilities.
See Figures 8 and Example Flash Extension Tolerances are based on weight of the forging after trimming, and related to the amount of flash extension.
9. APPENDIX A – TOLERANCES FOR IMPRESSION DIE | Forging Industry Association
Die Wear Tolerances for all length, width and diameter dimensions over mm or 30 in. Die Closure Tolerances relate to variations in thickness of forgings as affected by forgjng closing of the dies and die wear, and pertain to variations in dimensions crossing the fundamental parting line. Radii Tolerances are expressed as decimal millimeter in units of 0.
Over 30 to 50 incl. The experience of producers and purchasers of forged ix and products indicates that the tolerances set forth herein will provide adequate dimensional accuracy for most applications.
Is Die Steel Forging Standard – Free Download PDF
There are several special ways of providing closer tolerances on selected dimensions on forgings with added operations. Decimals used in computing tolerances are totaled and raided to the next highest 0. If draft is removed as result of trimming, broaching or punching, the minus radius tolerance 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.
Die Wear Tolerances on internal dimensions are expressed as minus values only. Tolerance on Internal Dimension.
Straightness Tolerance applied to flat portion. In such cases, the requirements of the forging should be confirmed by purchaser and producer in advance of production. Allowances for die wear occuring on dimensions measured perpendicular to the fodging parting line of the dies are included in Die Closure Tolerances Table II. Greatest dimension x Straightness Tolerance. See Table II, below. Where purchaser specified stock for machining, toleranc imperfections are commonly permitted to within 1.
IS 3469-1 to 3: Tolerances for Closed Die Steel Forgings
Radii Tolerances are plus or minus one-half the specified radii, except where corner radii are affected by subsequent removal of draft by trimming, broaching or punching. Area at the Trim Line Flash not included, expressed in square inches.
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 Largest Diameter mm x Die Wear Tolerance factor.
The tolerances set forth herein represent what the Forging Industry Association believes to be typical within the industry, as determined by actual measurements of forgings produced under normal operating conditions on standard forging equipment. It is equally important that the purchaser provide drawings of the finish machined part, or equivalent information. 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: Straightness Tolerances are expressed as decimal inch, in units of 0. Flat and thin with protrusion at right angles to the parting line.
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. From the highest to lowest point of contour.
Is.3469.1-3.1974 Die Steel Forging Standard
The Tolerance on flat portion is computed first: Length x Die Wear Tolerance factor. Weights of Forgings After Trimming, in kilograms. Minimum Finish Stock Per Surface. Die wear varies according to the material that is forged and the shape of the forging. Where surfaces of forgings are intended for use in “as forged” condition, surface imperfections are commonly permitted as shown in Table VI. Tolerance on Length Dimension. Appropriate value from Table V.