What are the common terms in the steel industry

1. Standards are uniform rules for repetitive things and concepts. It is based on the comprehensive results of science, technology and practical experience, subject to the consensus of the parties concerned, approved by the competent authorities, and issued in a specific form as a guideline and basis for common observance. Our iron and steel products execution standards include national standards (GB, GB/T), industry standards (YB), local standards and enterprise standards.

2.Technical conditions The performance indicators and quality requirements stipulated in the standards are called technical conditions, such as chemical composition, overall size, surface quality, physical properties, mechanical properties, technological properties, internal organization, delivery status, etc.

3.Guarantee conditions In accordance with the provisions of the technical conditions of metal materials, the manufacturer should carry out the inspection and ensure that the inspection results meet the requirements of the performance, chemical composition, internal organization and other quality indicators, called guarantee conditions.

4.The production of metal materials is the same as the production of other industrial products, which is carried out in accordance with the unified standard provisions, the implementation of the product delivery inspection system, unqualified metal materials are not allowed to be delivered. For metal materials delivered, the manufacturer provides a quality certificate to guarantee their quality. The quality certificate of metal materials not only states the name, specification, number of delivered pieces, weight, etc., but also provides all the inspection results of the specified guaranteed items.

5.Quality certificate is the supplier's confirmation and guarantee of the inspection results of the batch of products, and also the demander's reinspection and use based on 5 quality grade according to the requirements of steel surface quality, shape and size allowable deviation, the quality of steel is divided into several grades. Such as grade one, grade two. Sometimes for a certain requirement to develop different grades, such as surface quality is divided into a level, two, three, for surface decarbonization layer depth is divided into a group, two groups, etc., are the difference in quality.

6.Precision grade For some metal materials, the standard provides that there are several sizes allowed deviation, and according to the size allowed deviation size is different, divided into a number of grades, called precision grade. Accuracy grade can be divided into ordinary accuracy, higher precision and advanced accuracy according to allowable deviation. The higher the accuracy level, the smaller the allowable size deviation. When ordering, the accuracy level requirements should be written into the contract and other relevant documents.

7.Grade 7 The grade of a metal material is the name given to each specific metal material. The grade of steel is also called steel. The brand of Chinese metal materials generally can reflect the chemical composition. The brand not only indicates the specific kind of metal material, but also can be roughly judged according to it. In this way, the brand simply provides a common concept of the quality of specific metal materials, so as to bring great convenience to the production, use and management.

8.The varieties of metal materials refer to the products of different uses, shapes, production processes, heat treatment states, particle size, etc.

9.Model 9 The model of metal materials refers to the code of different shapes and types of profiles and hard alloys, which uses pinyin (or Latin) letters and one or several numbers. The number indicates the nominal size of the main part.

10.Specifications Specifications refer to different sizes of the same type or type of metal material. General size is different, its allowable deviation is also different. In product standards, the specifications of varieties are usually listed in order, from smallest to largest.

11.The surface state is mainly divided into two kinds: bright and not bright. Common in steel wire and steel strip standards, the main difference is to take bright annealing or general annealing. There are also polishing, polishing, pickling, coating as a surface state.

12.Edge State Edge state refers to whether the strip is edged or not. The cutting side is the cutting strip, and the uncutting side is the uncutting strip.

13.Delivery Status Delivery status refers to the final plastic deformation machining or final heat treatment status of the product delivered. Deliveries without heat treatment are hot rolled (forged) and cold rolled. Delivery after normalizing, annealing, high temperature tempering, tempering and solid solution treatment is collectively referred to as the state of heat treatment, or according to the type of heat treatment respectively called normalizing, annealing, high temperature tempering, tempering and other states of delivery.

14.The degree of hardness of the material refers to the degree of hardness of the steel obtained by different heat treatment or work hardening. In some strip standards, it is divided into extra mild steel strip, mild steel strip, semi-mild steel strip, low hard steel strip and hard steel strip.

15.Longitudinal and transverse steel standards in the longitudinal and transverse refers to the relative relationship with rolling (forging) and drawing direction, parallel to the direction of processing called longitudinal; Perpendicular to the direction of processing is called horizontal. The sample taken along the processing direction is called longitudinal sample; Samples taken perpendicular to the direction of processing are called transverse samples. The fracture on the longitudinal sample is perpendicular to the rolling direction, so it is called transverse fracture; The fracture of the transverse sample is parallel to the direction of processing, so it is called the longitudinal fracture.

16.Theoretical Quality and Actual Quality These are two different ways of calculating the quality of delivery. Delivery by theoretical quality refers to the quality of delivery calculated according to the nominal size and density of the material. According to the actual quality of delivery, is according to the material after weighing (weighing) the quality of delivery.

17.Nominal size and Actual size Nominal size refers to the nominal size specified in the standard, which is the desired size in the production process. But in the actual production, the actual size of steel is often greater than or less than the nominal size, the actual size, called the actual size.

18.Deviation and tolerance Because it is difficult to reach the nominal size in actual production, the standard stipulates that there is an allowable difference between the actual size and the nominal size, which is called the deviation. A negative difference is called a negative deviation, and a positive difference is called a positive deviation. The sum of the absolute values of the allowable positive and negative deviations specified in the standard is called the tolerance. Deviations are directional, that is, expressed as "positive" or "negative", and tolerances are not directional

19.In the current standard, there are four kinds of provisions on the length of steel delivery:

Measuring length, where the steel length in the standard range and no fixed length, are called the usual length. But in order to package transportation and metering convenience, the enterprise shear steel, according to the situation is best cut into several different length size, and strive to avoid chaos.

20.Is called short ruler length

Smelting method refers to the type of steelmaking furnace used for smelting, such as open hearth furnace, electric arc furnace, electroslag furnace, vacuum induction furnace and mixed steelmaking. The meaning of the term "smelting process" in the standard does not include the concepts of deoxidation methods (e.g., fully deoxidized, semi-deoxidized, semi-sedate and boiling steels) and casting methods (e.g., injection, casting, continuous casting).

2l.Chemical composition (product composition) refers to the chemical composition of steel products, including principal components and impurity elements, whose content is expressed as a percentage by weight.

22.Melting composition The melting composition of steel refers to the chemical composition of steel in the middle stage of pouring after the completion of melting (such as deoxidation in the tank).

23.Finished Product composition The finished product composition of steel, also known as the verification analysis composition, refers to the chemical composition obtained from the finished steel according to the specified method (see GB/T222 for details) drilling or planing test chips, and according to the specified standard method analysis. The finished components of steel are mainly used for the acceptance of steel by the user department or the inspection department. Manufacturers generally do not do complete analysis of the finished product, but should ensure that the composition of the finished product conforms to the standard. For some major products or sometimes for some reason (such as process changes, quality instability, melting composition close to the upper and lower limits, melting analysis is not available, etc.), the manufacturer also does the composition analysis of the finished product.

24.High quality steel and high quality steel (with A word), also known as quality steel and high quality steel, the difference is that high quality steel in the following aspects of some or all of the better than high quality steel.

① reduce the range of carbon content; (2) reduce the content of harmful impurities (mainly sulfur and phosphorus); (3) Ensure higher purity (refers to less inclusion content); (4) Ensure high mechanical properties and technological properties.