(1) The boron content is too high, which is disadvantageous for products requiring good comprehensive mechanical properties such as bolts, screws and studs. Moreover, in the current relevant technical standards for steel products, there is a lack of restrictions on boron. Therefore, this standard is necessary to limit the composition of boron. Note: Because GB/T3098.1-2000 standards use mechanical property terms, this article is the unification of the narrative, the whole article uses the term mechanical properties. (2) The new standard modifies the phosphorus and sulfur content of fastener materials above 8.8 strength, so that the content of harmful elements such as phosphorus and sulfur is changed from 0.04% and 0.05% respectively to the same value of 01035%. It is consistent with the current technical requirements for steel 1 (GB/T699-1999 and GB/T3077-1999). (3) New and old standards have the minimum tempering temperature regulation for 8.8 grade fastener products. The new and old standard minimum tempering temperature is compared with the performance standard grade material minimum tempering temperature old standard new standard. The new standard adds four technical indicators of breaking torque, reduction of area, hardness after tempering and surface defects in the mechanical and physical properties of fasteners specified. The new standard adds provisions for the maximum value of the end hardness measurement. According to the provisions of this standard, the hardness of bolts, screws and studs is measured at the head, end or rod. When the end is selected for measurement, the maximum hardness should be 250HV, 238HB or 99.5HRB. This is the old standard. No. Flexible lift gate is a flexible soft curtain door, inside and outside the two curtains, curtains used between the aluminum beams connected with a vertically movable rail, the roof beams have levels not in the same straight line and hangar large plants in particular be applicable. Flexible lift door installation does not take up interior space in the hole inside. When the fiest move to open the door, and finally superimposed over the hole. Off event curtain rail first and then fall down until it is completely closed. Flexible Gate,Flexible Pvc Aircraft Folding Up Door,Steel Structure Fabric Flexiile Door,Exterior Automatic Flexible Door Shenzhen Hongfa Automatic Door Co., Ltd. , https://www.pvchighspeeddoor.com
Performance level firmware standard
(1) The boron content is too high, which is disadvantageous for products requiring good comprehensive mechanical properties such as bolts, screws and studs. Moreover, in the current relevant technical standards for steel products, there is a lack of restrictions on boron. Therefore, this standard is necessary to limit the composition of boron. Note: due to GB/T3098. 1-20