Opinions about Grain Refinement and Embrittlement-cracking Resistance as Described in Contents of Two Patents

Described here in the essay are the protection scopes of the two austenite stainless steel tube-related patents as applied in China by Sumitomo.Taking the S30432 and TP347H steel tubes involved in the patents as examples,the chemical composition and grain refinement stability reproducibility tests are carried out to the S30432 steel tube,and the S equivalent and the Nb equivalent as affecting its embrittlement cracking are calculated.It is regarded that the claim for the content ranges of Ti and O as specified in the first patent covers the normal metallurgical residual contents,and the claim as described for the range of chemical composition in the same patent is unreasonable;the description that reheating does not coarsen the grains in the "embodiment" of the patent fails to reappear;the S equivalent and Nb equivalent values of all the S30432 sample tubes meet the provisions of the second patent,which should be the normal metallurgical results of the S30432 steel,therefore in this case what is proposed in the second patent is just a method to judge the resistance against embrittlement cracking tendency of the austenitic heat-resistant stainless steel,and should not be understood as a new invention of the embrittlement cracking-resistant material.