Test of BibT E X references

Deep drawing steel is strengthened by alloy-nitrogen precipitation strengthening to a minimum average yield strength of 50 ksi. A deoxidized, low carbon steel sheet stock or article formed therefrom, containing from about 0.02 percent to 0.2 percent titanium in solution, from about 0.025 percent to 0.3 percent columbium in solution, from about 0.025 percent to about 0.3 percent zirconium in solution, alone or in admixture, is heat treated at 1,100 DEG - 1,350 DEG F in an atmosphere containing ammonia in an amount insufficient, at the temperature and time involved, to permit formation of iron nitride.