Difference Between ASTM A-36 & S-275 JR. Difference Between ASTM A-36 & S-275 JR. ZAbbas101054 (Materials) (OP) 28 May 14 01:15 Hi, Could someone explain the major difference between A-36 & S-275 JR materials ? Thanking you all in advance. Cares. RE: Difference Between ASTM A-36 & S-275 JR. Ron (Structural) 5 Jun 14 09:36 A36 has a yield strength of 235 mPa and S275JR has a yield of 275 mPa. A36 has a lower carbon content as well. There are other differences. It would be better to compare both standards side-by-side than picking pieces of each for comparison.