We often encounter American system (according to the thread mark to judge whether it is imperial or American). 8th, 5.1th, and 2nd grades are completely different from the A194 grade 2. See ASTM A 194-2000 for carbon for bolts and nuts. Steel, alloy steel and stainless steel) or " The following table tells you the grade and performance requirements of American external thread products. Note: 1, 1psi=0.006895MPa Dryback Floor,Double Copper Floor,Copper Floor,Indoor Dryback Floor DONGYANG MAOSHENG PLASTIC CO.,LTD , https://www.maoshengflooring.com
"Which logo, what do these mean, what is the specific mechanical performance, what performance needs to be tested during inspection? 
2. Guaranteed load: The ultimate load that the thread product does not produce obvious plastic deformation, which is determined by the product of the thread stress cross-sectional area of ​​the product and the guaranteed stress.
3, full size: is the tensile test piece is a complete fastener product before the state of use.