In our daily life, stainless steel fasteners have been widely used. In order to enable everyone to better understand stainless steel, below, Shengxin Fasteners will introduce some small knowledge of stainless steel fasteners.
1. Small knowledge of stainless steel lock nuts
Ordinary nuts will loosen by themselves due to vibration and other reasons during use, such as vibration. In order to prevent this phenomenon, self-locking nuts were invented. The function of the self-locking nut is mainly anti-loosening and anti-vibration. For special occasions.
Its working principle is generally that the general nut will loosen by itself due to vibration and other reasons during use, such as vibration. In order to prevent this phenomenon, the self-locking nut was invented.
The function of the self-locking nut is mainly anti-loosening and anti-vibration. For special occasions.
Its working principle is generally self-locking by friction. The types of self-locking nuts classified by function include those with embedded nylon rings, those with neck closures, and those with metal anti-loosening devices.
2. Marking of stainless steel group and performance grade of stainless steel nuts
The marking of stainless steel nuts consists of two parts: the steel group marking and the performance grade marking, separated by a dash.
Steel group markings consist of either a letter or a number. The letters indicate the type of steel, and the numbers indicate the chemical composition range of this type of steel. Among them, A-represents austenitic steel; C-represents martensitic steel; F-represents ferritic steel.
Marking of performance grade: For (type 1) nuts with nominal height m≥0.8D, it consists of two numbers, which represent 1/10 of the guaranteed load stress; for (thin) nuts with nominal height 0.5D≤m<0.8D, It consists of three numbers, (from the left) the first digit "0" indicates the nut with reduced bearing capacity, and the last two digits also indicate 1/10 of the guaranteed load stress. Here are a few examples:
A2-70: means austenitic steel, cold-worked, the minimum guaranteed stress is 700MPa (type 1 nut);
C4-70: Indicates martensitic steel, quenched and tempered, the minimum guaranteed stress is 700MPa (type 1 nut);
A2-035: means austenitic steel, cold-worked, the minimum guaranteed stress is 350MPa (thin nut);
3. How much do you know about the main characteristics of stainless steel screws?
The definition of stainless steel screws refers to self-tapping screws that do not need to be used with nuts. The thread is self-tapping and the tail is sharp. When the triangular tooth self-extruding screw is screwed into the hole on the plastic metal material, it will form an internal thread in the hole by extrusion and form a reliable locking thread connection.
Generally, it means that the thread is self-tapping, so that the self-tapping effect does not need to be used with nuts. There are many classifications of screw heads, such as outer hexagon head, pan head, countersunk head, and inner hexagon head. Umbrella heads, head pads, etc. The tail is generally pointed. Make self-tapping effect.
Self-tapping screws are also called self-tapping screws. The names are different, but the meaning is the same. They are all self-tapping. The main function of self-tapping screws is that they do not need to be used with nuts, which saves a lot in terms of cost. There is no need to pay for the cost of nuts.
4. Main features Although there are many types of stainless steel screws, they all have the following main features:
(1) Generally, they are made of carburized steel (accounting for 99% of the total products). It can also be made of stainless steel or non-ferrous metals.
(2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel screws must be solid solution hardened. In order to make self-tapping screws meet the mechanical properties and performance required by the standard.
(3) The product has high surface hardness and good core toughness. That is, "soft on the inside and strong on the outside". This is a major feature of the performance requirements of stainless steel screws. If the surface hardness is low, it cannot be screwed into the matrix; if the core toughness is poor, it will break when twisted, and it cannot be used. Therefore, "soft on the inside and rigid on the outside" is a self-tapping screw that meets the performance requirements.
(4) The surface of the product requires surface protection treatment, usually electroplating treatment. The surface of some products needs to be treated with phosphate (phosphating). For example: wallboard self-tapping screws are mostly phosphating.
(5) Produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine to ensure product quality. The head of the self-tapping screw produced in this way is well formed and the thread quality is high.
Small knowledge of stainless steel fasteners
2022 12/01