Blockboard can be divided into "excellent products", "first-class products" and "qualified products" according to the quality of the materials and the texture of the surface materials. Some enterprises also mark the grades of grades as A, double A and triple A, but this is only corporate behavior. There is no “3A grade†in the national standards. This kind of labeling is not allowed on the market. There are many kinds of core materials in the core of the core board, such as poplar, birch, pine, paulownia eucalyptus, etc. Among them, poplar and birch are the best, the texture is dense, the wood is not soft and hard, the nail holding power is strong, and it is not easy to be deformed. . The texture of Paulownia is soft, absorbs large water, and is not easy to dry. During the use of the plate, when the water evaporates, the plate is easy to dry and deform. The hard wood is hard, not easy to press, the splicing structure is not good, the nail holding power is poor, and the deformation coefficient is large.
The face material may be one or two layers of veneers respectively on both sides of the core, and may be classified into three layers of blockboard and five layers of blockboard, and the face materials are further divided into willows, eucalyptus and teak according to the tree species. , eucalyptus, etc. The surface of the high-quality core board with good quality is smooth and smooth, and it is not easy to warp and deform. According to the sanding condition of the surface material, the board can be divided into two types: one light and two light.
Wear-Resistant Ball Valve,Wear Resistant Ball Valve,High Hardness Wear-Resistant Ball Valve,Ball Valve With Pressure Relief
Chongqing Xingjida Import and Export Trade Co., Ltd. , https://www.xjdvalve.com