As an important part of metal processing, heat treatment has a decisive influence on the performance and quality of rectangular tubes.
First of all, we need to understand the basic characteristics of rectangular tubes. Rectangular tubes are a kind of low-alloy high-strength structural steel tubes with excellent mechanical properties and corrosion resistance. This kind of steel tube is mainly used to manufacture various structural parts and mechanical parts, and has a wide range of applications in construction, energy, machinery and other fields. However, in order to meet the special requirements of steel tube performance in different fields, a series of heat treatment processes are required.
The main purpose of heat treatment is to change the internal structure of steel by controlling the heating and cooling process, thereby improving its performance. For rectangular tubes, heat treatment can further improve its yield strength, tensile strength and corrosion resistance. Common heat treatment methods include normalizing, tempering, quenching, etc.
Normalizing is the process of heating steel to a temperature higher than the critical point, maintaining it for a certain period of time, and then cooling it naturally in the air. Normalizing can eliminate the internal stress and structural defects generated by the steel pipe during the rolling process, refine the grains, and thus improve the strength and toughness of the steel pipe. For rectangular tubes, normalizing can effectively improve their overall performance and meet the use requirements under various complex working conditions.
Tempering is the process of heating the steel to a certain temperature range after quenching, keeping it warm for a period of time and then cooling it. Tempering can eliminate the internal stress and brittleness caused by quenching and improve the plasticity and toughness of the steel pipe. For rectangular tubes, proper tempering treatment can optimize its organizational properties and increase the service life of the steel pipe.
In terms of production technology, rectangular tubes use advanced production technology and equipment to ensure the stability of product quality and performance. In the production process, firstly, high-quality seamless steel pipes are selected as raw materials, and then the shape of rectangular tubes is formed through cutting, bending, welding and other processes. Subsequently, the performance and quality of rectangular tubes are further improved through heat treatment, surface treatment and other processes. In the production process, the quality of each link is strictly controlled to ensure the reliability and stability of the product.
Standard requirements for rectangular tubes
ASTM A500: This is a standard issued by the American Society for Testing and Materials (ASTM) that covers the requirements for cold-formed welded and seamless rectangular tubes. The standard specifies the dimensions, chemical composition, mechanical properties, and other requirements for rectangular tubes.
EN 10219: This is a standard issued by the European Committee for Standardization that specifies the requirements for cold-formed welded structural steel rectangular tubes, seamless rectangular tubes, and hot-formed welded structural steel rectangular tubes.
GB/T 6728: This is a Chinese national standard that specifies the dimensions, appearance, weight, and allowable deviation requirements for cold-formed welded rectangular tubes, seamless rectangular tubes, and hot-formed welded rectangular tubes.
JIS G3466: This is a Japanese industrial standard that specifies the dimensions, chemical composition, mechanical properties, and other requirements for hot-formed welded and cold-formed welded rectangular tubes.
These standards usually specify the size range, allowable deviation, chemical composition, mechanical properties (such as tensile strength, yield strength, elongation, etc.), and testing methods of rectangular tubes. When selecting and using rectangular tubes, you should choose the standards that meet the requirements for production and procurement based on the specific engineering requirements and national/regional regulations and standards.
In general, heat-treated rectangular tubes have high strength and good compressive properties and are often used in applications that require high structural strength. Rectangular tubes are very simple to produce and manufacture to meet the needs of unique projects. They can be cut, welded, bent, drilled and molded into a variety of shapes, allowing them to be seamlessly integrated into complex structures. Simple manufacturing can save time and money throughout the construction or production process.