1、f W .- e E c i (3 .e E 5 - f E: i Y UDC 621.73.042422.1 : 669.14 DEUTSCHE NORMEN October 1971 : 621.753.1 I - Steel Forgings hchining Allowances and Permissible Variations for Open-die Forged Diacs LN 7527 Sheet 1 Schmiedestcke aus Stahl; Bearbeitungezugaben und zulassige Abweichungen fr freiformges
2、chmiedete Scheiben Dimenaions in mm - Piie Standard applies to open-die forged disce produced by forging down and upsetting by hammers - or preeees. It appliee to disca the forging dimeneions of which satiefy the following conditions: 0.1 d2 S h2 5 1.5 d2 2. Dimensions. deeiunatioq Desifnation of an
3、 open-die forged disc with finished dimensions d, - 280 mm and hl = 125 mra ac- cord ng to forging grade 2, in C 35: DiSc 280 x 125 F DIN 7527 - C 35 A distinction is made between finished dimensions and forging dimensions. Open-die forged discs are to be ordered on the basis of the finished dimenei
4、ons. me forging dimensions 62 and h2 are calculated from the finished dimeneions dl and hl and the values of the machining allowances 2 CI and 2 22 found from Table 1. me values of Table 1 a ply to dl and hi; for each machined surface they are half the values stated. !Be finished dimens!ons determin
5、e the machining allowancee “1 and 22. Steel forgi%; machining allowances and permissible variations for open-die forged pierced discs, see D 7527 Sheet 2 -; for seamless open-die rorged rings, see DIN 7527 Sheet 3 -; for seamlese open-die forged buehes, see DIM 7527 Sheet 4 -; for open-die forged ro
6、lled and welded ringe, e88 DIN 7527 Sheet 5 Continued on pages 2 and 3 Ioinvorkouf dor NormbltIor durch Beuth-Vertriob GmbH, Berl+ 30 und Kln DIN 7527 BI. I engl. Preisgr. Page 2 3. Machining allowances and DermiSSible variations With regard to machining allowance8 and permissible variations a disti
7、nction ii made between: FOrRinR grade F for normal standard of accuracy Forninu made E for more exacting requirements Forging grade E generally calls for the use of special tools and additional manufacturing ef- fort and is therefore only a proposition when mlatively large quantities are involved. D
8、IN 7527 Sheet 1 Table I. Machininn allowances Foriring mado E 5 4 3 -5 i- aw) 6 56 6-d - .- 890 315 400 I 10 1 8 Il0 8 10 9 11 10 400 SW I - I - I12 10 12 11 13 12 - 11111 12 1 11 I 13 I 12 I 14 I 14 - 14 12 IS 13 16 15 16 14 17 15 18 17 N 16 21 17 22 19 _ ._ - -7-t sl81io7-1-1- ,1111 -+m 9 10 10 11
9、 11 12 13 26 - The iizes above the stepped line should be avoided where possible. ExamDie 1: Forninu dimensions Finished dimensions: dl = 280 mm, hq - 125 mm Machining allowances according to forging grade F for dl = 11 mm, Forginn dimensions: d2 - 280 + 11 = 291 mm, h2 = 125 + 10 = 135 mm The Tablf
10、 2. They are determined by the forging dimensions. - IO mm emissible variations for the calculated forging dimensions d2 and h2 are found from “able 2. Permiesible variations ExamDle 2: Permissible variationa Forging dimensions: da permissible variations according to forging grade F for dp 2 4 mm, h2 f 4 mm 291 mm, h2 - 135 mm 4. Material This Standard applies to open-die forged discs made of unalloyed and low alloy engineering and tool steel with a carbon content up to 0.9 % or other alloying componente totalling 4 %max.
