Views: 0 Author: Site Editor Publish Time: 2023-01-22 Origin: Site
A high-tensile bolt is one of the most commonly used fasteners in the industry, which is made of high-strength steel or bolts that require force. And the processing process of the high tensile bolt has steel design, spheroidal annealing, shelling and phosphorus removal, drawing, cold forging and forming, thread processing, heat treatment, and other processes. Let's take a look at the details.
Here is the content list:
l Steel design
l Spheroidized annealed
l Shelling and Phosphorus Removal
l Pulling process
l Cold forging
l Thread processing
l Heat treatment
In high tensile bolt manufacturing, the correct choice of fastener material is an important part, because the performance of high tensile bolt and its material has a close relationship. If the material selection is improper or incorrect, it may cause the performance to fail to meet the requirements, shorten the service life, even accidents or processing difficulties, manufacturing costs, etc. Therefore, the selection of bolt material is a very important link.
Countersunk head screws and hexagonal cylindrical head bolts such as high tensile bolts in the use of cold rolling process production, the original organization of the steel will directly affect the cold rolling process forming ability. In the cold rolling process, the local area of plastic deformation of up to 60%-80%, so the steel must have good plasticity. When the chemical composition of steel is determined, a metallographic organization is a key factor to determine the quality of plasticity. It is generally believed that large pearlite is not conducive to cold rolling forming, and small spherical pearlite can significantly improve the plastic deformation ability of steel.
Cold heading steel coils to remove iron oxide plate process for stripping bright, phosphorus removal, there are two methods of mechanical phosphorus removal and chemical pickling. Mechanical phosphorus removal instead of the chemical pickling process of the coil, both to improve productivity and reduce environmental pollution. This phosphorus removal process includes the bending method (commonly used with triangular groove wheel reverse bending coil), and spray nine methods, phosphorus removal effect is good, but can not make the residual iron phosphorus to net (iron oxide removal rate of 97 %), especially when the iron oxide adhesion is very strong, therefore, mechanical phosphorus removal by the iron thickness, structure and stress state, most of the use of low strength fasteners with carbon steel coil. And high tensile bolts with coils in the mechanical phosphorus removal, to l, remove all the iron oxide, but also by the chemical pickling process that compounds phosphorus removal.
The drawing process has two purposes, one is to reform the size of the raw material; the second is to make the high tensile bolt obtain the basic mechanical properties through the deformation strengthening effect, for medium carbon steel, medium carbon alloy steel has another purpose, that is, to make the coil control cooling to get the sheet carburized body in the drawing process as cracked as possible, for the subsequent spheroidal annealing to get the granular carburized body ready.
Typically, high-tensile bolt heads are formed using cold-head plastic processing. Compared with the cutting process, the metal fibers (metal wires) are continuous along the product shape without cutting in the middle, which improves the strength of a high-tensile bolt, especially the excellent mechanical properties. And the cold head forming process includes cutting and forming, single-stop click, double-strike cold head, and multi-stop automatic cold head.
The high tensile bolt is generally cold processed so that the threaded blank within a certain diameter range is passed through the thread rolling plate, and the thread is shaped by the pressure of the plate. The threaded part of the plastic flow is not cut off, strength is increased, precision is high, and quality is uniform, so it is widely used. The thread diameter required to produce the thread outside diameter of the final product varies, as it is limited by the thread accuracy, the material with or without coating, etc.
High tensile bolt is tempered according to technical requirements. Heat treatment tempering is used to improve the overall mechanical properties of the fastener to meet the tensile strength value and flexural strength ratio specified in the product. Since the high tensile bolt is produced in large quantities and at a low price, and the threaded part is a relatively fine and precise structure, heat treatment equipment is required to have a large production capacity, a high degree of automation, and good heat treatment quality.
The above is the relevant content about the processing process of the high-tensile bolt. If you are interested in a high-tensile bolt, you can contact us, our website is www. suqingfasteners.com. I look forward to your arrival very much and hope to cooperate with you.
