Nowadays, many fields have their own professional terms. For example, the auto repair industry, the chef industry and other fields have their own professional terms, and our seamless steel pipe factory is no exception. We also have professional terms. If you don’t understand it, you may come down and let the seamless steel pipe manufacturer take you with you to understand it.
A. Nominal size: it is the nominal size specified in the standard, the ideal size expected by users and manufacturing enterprises, and the ordering size indicated in the contract. Seamless steel pipe has hollow section and is widely used as pipeline for conveying fluid, such as pipeline for conveying oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe has lighter weight when its bending and torsional strength is the same. It is an economic section steel. 20G high pressure boiler tubes have strict requirements for the steel grades used in the manufacture of steel tubes. 20G high pressure boiler tubes are often in high temperature and high pressure conditions when used. The tubes will be oxidized and corroded under the action of high temperature flue gas and steam. The steel pipe is required to have high lasting strength, high anti-oxidation and corrosion performance and good structural stability. High pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, air ducts, main steam tubes, etc. of high-pressure and ultra-high-pressure boilers.
B. Actual size: the actual size obtained in the production process, which is often greater than or less than the nominal size. This phenomenon of being larger or smaller than the nominal size is called deviation. Deviations and tolerances
A. Deviation: in the production process, because the actual size is difficult to meet the nominal size requirements, that is, it is often greater than or less than the nominal size, the standard specifies that there is a difference between the actual size and the nominal size. If the difference is positive, it is called positive deviation, and if the difference is negative, it is called negative deviation.
B. Tolerance: the sum of positive and negative deviation values and absolute values specified in the standard is called tolerance, also known as “tolerance zone”.
Deviation is directional, i.e. “positive” or “negative”; Tolerance is not directional, so it is wrong to call the deviation value “positive tolerance” or “negative tolerance”. Delivery length
Post time: Feb-14-2022