What are the standards for stamping elbows?

The standards for stamping elbows are as follows:

Chinese national standard for elbows:

GB/T12459-2005；

GB/T13401-2005；

GB/T10752-1995；

Petrochemical standard for elbows:

SH 3408-1996；

SH 3409-1996；

Chemical standard for elbows: HG/T 21635-1987;

Electrical standard for elbows: DL/T695;

Petroleum standard for elbows: SY/T 0510;

German standard for elbows: DIN2605;

Japanese standard for elbows: JIS;

Marine standard for elbows: GB/T10752-1995;

Chemical standard for elbows: HG21631-1990.