Micro eng A 182 F 22 Cl 1-UNS K 21590- is Cr-Mo (2.25 Cr-1.0 Mo) forging with T.S 415 MPa with forged /HT hardness around 170 BHN. A 182 F 22 - Cl 3- - UNS K 21590- is also Cr-Mo with T.S around T.S 515 MPa with hardness in the range 160-210 BHN. These are meant for forged fittings for valves and high temperature parts. Since your intended service is meant for boilers, vendor is correct in asking to specify A 336 F 22 or F 22 A 336 F 22 A A 336 F 22 / F 22 A is for alloy steel forgings for pressure and high temperature parts with minimum tempering temp around 675 deg cent specified while ordering since this conforms to specified temperature temp limits for optimum ductile properties. Cost wise both should be more or less same. You have to order A 336 F 22 or A336 F 22 A to suit your boiler drum requirements and specify supplementary tests to meet the same. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India August 16, 2009 E-mail: nishi@vsnl.com >Hi Dears >I am not a material specialist . >I am a equipment designer. We want to order some Reactors. >One of reactor's vendors ask me to change forging material >for nozzles from A 182 F22 cl2 to A 336 F22 cl.3 >I saw ASTM and I couldn't find Cl.2 for A 182 , and also I >couldn't find any descreapancy between A 182 F22 and A336 >F22. >can I approve using of A 336 F22 instead A182 F 22?! >Generaly which one is better and more expensive? >Best Regards

Microeng There is no Cl 2 for A 182 F 22. You can think of A 336 F 22 or F 22A for your Reactor job Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Aug 17 E-mail: nishi@vsnl.com >Thank u CVSRINIVASAN >Our concern was Hight Temp. Reactors and not boillers. >I underestood that there is no problem to change A182 F22 >with A 336 F22 >. >But what about Class? >is threre Class 2 for A 182 F22? >or is Class 3 best Class for A336 F 22?