1、 This document has been reproduced from the best hardcopy available * -_. - - 2 m Manufacturing Standards 0 U-HI 1-6 NORMALIZING AND ANNEALING OF STEEL FOFIGINGS -. . !. 9-00 ._ -z-z Ttsi s urccess standard defines the acceptabie processc?- = suiia!:le in- tI!e rxn-real ix i nq , stress-relieving,
2、soft-anneal i n3 or i sothermal annealing of c,CceI forgings, to obtain specific mechaulical .properties and micrnstt-u+ures for optimum mechanibility. fdormalizing or annealin may be performed in qas. oil-f ired or eiectricaily heated batch or continuous furnances. For optimum results and c!xksCmcy
3、 of product, mu1 ti-zone continuous f urrkances are preferred Y since more precise control of cooling rate is possible. Annealirlq in batch f!rnzqree is feasible? but strict czwkrol of loading weights is essett,!Sal. to permit use of the sensible heat of the charge to retard abd control the ro1 i ng
4、 rate. Isottermal anneal i nq normal I y requires a crw3ti nccws i:rnaceLI twt has been performed successf uil y, usirq k!lo batch iurnances ni tli e!xk-transfer. Selection of a particular process is pri.marily dqendent upon C,!W transformation characteristics nf khs steal and the size of khe iiv pi
5、 r:gs. in gewral ? alt increase in alloy content of the steel requires hilter rustenitizing temperatures, longer oeriods at Le.m.peratuf-e enrf fflore f-inability is generally applied to forginas of r!lo/crl steel. It may, hcwever, also be employed fcr unalloyed stkls, if heat. ! reatmcwit. in accor
6、dance wj th Section 2. i is not adequate. .anufactwing Administration HEAT TAEATEYENT U-H1 1-6 Page i of S Juue 1996 Manufacturing Standards B ?w-qings shail be heated to austenitizing tcmnerature kh?n beinl av=:qle!i . . -c /a!- machivaf:i 1 i ty and he!?cJ at this Campevai.!rre for c7 s!.!t fi iri
7、nt pPri+ (35 - Ai! dtinwtesj . Controi led cool it-q to WOoC - !+:y -tfift, il.i!?L;rW” !.Ji if, fl4Lllr,r ccmllrig in air or forced air (blw5r!. p? i di no temoet-ature decreases. a. !7ifiCl fl!l!iti -ZCtRP, continueus furnances the tem?eraLwe OF tnnes i 5 steppxi j:-,r, -*. from the austeni tizi
8、ng zone to the discharge zone. For rarburizing StORiP, scch as WE Scth=rmai transformation into theliat all emp!oyees ass:.ir:ia!:ed ci i.ii thnse prncasses be weli trained, and instructed to follow the iaid do:m r?!sraiing artd safety procedures. This training s!iaj 1 be rqehted at ro:?uS ar interv
9、als. U-H1 7-6 Page I of 5 June 19% HEAT TREATEUENT : ;/)_ _. . TAEiE I .,:. . . . . : :. “j _ , .,;, _,. ;. : . Recommended Austenitizing Temperatures T- . , ? of Steel Hardness Specification for Forgings and Recommended Heat-Trestoent Processes Iiardmss HE 121 - 170 143 - 192 156 - 217 136 - 223 156 - 229 1s - 241 130 - 187 145 - 197 149 - 187 241- -341 156 - 147 149 - 179 i43 - 187 17Q - 211 170 - 227 179 - 223 137 - 207 149 - 197 149 - 187 156 - 2!? 156 - 229 x X i ,. X X x X x X i: . . x x x X x x % Manufacturing ninis:ration HEAT TREATEWENT u-IIT l-6 Page S/End June 1996
