tensile strength of astm A672Gr.55

Tensile strength is the minimum force that the specimen withstands without suffering a failure.

Breaking strength is that force which is required to break the specimen.

Tensile modulus is the ratio of tensile stress to tensile strain.

Tensile modulus is the ratio of tensile stress to tensile strain.

I'm not sure if your referring to 400C or 400F.

But, according to Shigley's Mechanical Engineering Design, 8th edition by Budynas and Nisbett.

The tensile strength of 1050 steel quenched and tempered at 400F (205C) is 1120 MPa (163 kpsi).

The tensile strength of 1050 steel quenched and tempered at 425C (800F) is 1090 MPa (158 kpsi).