The paper analyses minimal angle of defection in test machine dial(low accuracy),test piece glide,faint defintion(upper yield strength-lower yield strength-yield strength),different stress speed,so as to register errors,and puts forword correction.

Effect of phosphorus on the yield strength of as-quenched GH761 alloy;

Study of influence factors of yield strength of oil and gas pipeline;

A modeling study of the yield strength of HRB335 hot rolled ribbed bar;

Based on the plain carbon steel with the chemical composition of 200MPa class steel the products of the yield stress of 400～500 MPa class and high-quality mechanical properties can be produced using the technology of chemistry tightly-tuning and controlled rolling - controlled cooling.

From the tests, a two-stage linear relation has been found between yield stress(σ_s) and strain rate(ε),σ_s=σ_0+klgε.

Yielding behavior of mismatched welded joint and prediction of its yielding strength;

Mechanical properties of normalized and tempered 12Cr2Mo steel forgings,primarily yielding strength,were on the low side.

The effect of tensile rate on the lower yield strength of the iron and steel material was investigated,the advantage of the tensile rate of GB/T228-2002 was discussed.

Evaluation of uncertainty of measurement in testing for materials at ambient temperature has been discussed,including tensile strength;lower yield strength;proof strength,non-proportional extension;percentage elongation after fracture and percentage reduction of area.

According to GB/T228-2002 standard,"metallic materials tensile testing at ambient temperature",the lower yield strength of the cold rolled steel plate G450 has been tested.