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Cold Basic Knowledge Question And Answer

Anebon Metal Products Co.,Ltd | Updated: Oct 16, 2018

Cold sputum: It is the use of metal plasticity, cold pressure mechanics for pressure or cold drawing, to achieve the purpose of solid metal deformation.

A method of forging the top of a bar or wire at room temperature, also known as cold extrusion.

Mainly used to manufacture bolts, nuts, nails, rivets and steel balls.

The choice of metal material except carbon steel, but also copper, aluminum, alloy steel, stainless steel and titanium alloy, material utilization rate of up to 80 ~ 90%. Continuous, multi-station, and automated production through a dedicated cold heading machine (the world's largest cold heading machine exhibition - Shanghai Fasteners Professional Exhibition June 2015). In the cold heading machine, the processes of cutting, hoeing, accumulation, forming, chamfering, twisting, shrinking and trimming can be sequentially performed. The cold heading machine has high production efficiency and can reach up to 300 pieces per minute.

| Is the hexagonal head of the screw cold?

The vast majority are produced by the cold heading process, because this process saves time and materials.

Small-volume special or special bolt hex heads are milled after turning.

The forming of the hexagonal head of the bolt cannot be generalized. There are cold, hot piers, and the finished product directly after the smashing. There are also machining after the boring, and all machining.

How is the thread made?

Single-piece small batches can be used with die-threading, lathe picking, and cyclone milling. This method is inefficient, waste is generated, and raw materials are wasted.

When high-volume light bolts (cold boring) and wool bolts (hot tapping) are required to make threads, it is necessary to use a twisting machine, which is highly efficient and has almost no waste. At the Shanghai Fasteners Professional Exhibition, you can find the world's top manufacturer of silk reeling machines.

The production of ordinary screws is basically divided into two processes, the first is the head forming, the cold heading, the warming or the red hitting process; the second is the twisting, which is based on the previous process to make the threaded part. Most screws are subjected to surface treatment and heat treatment before leaving the factory.

|Example: Complete manufacturing process of 8.8-level hexagonal head galvanized bolt

   Wire Annealing---Pickling--Drawing--Head--Tooth--Heat Treatment--Electroplating--Packaging

|Noun explanation:

Annealing: A process of metal heat treatment that controls the hardness of the wire itself. A high temperature spheroidizing annealing furnace is generally used.

Pickling: It is to wash away the rust, impurities and the like on the surface of the wire.

Draw line: Refers to the cold drawing of the wire to the diameter you need to produce the bolt.

Cold-twisted wire: Wire after drawing, pickling or heat treatment, also known as cold-wired, finished screw wire.

Start: It is the name of the process of cold heading and extrusion of the bolt head. Typically, the manufacture of bolts larger than M24 (or 1 inch) in diameter does not employ a cold extrusion process.

Tooth decay or cavities: Threads are made by a boring machine or a thread rolling machine.

Heat treatment: heating and holding the final temperature drop through the industrial furnace, changing the metal crystal structure to achieve the corresponding performance level of the fastener.

Plating: A type of surface treatment, usually galvanized on the surface to achieve general anti-corrosion purposes.


Anebon Metal Products Co.,Ltd

Skype: jsaonzeng

Mobile: +86-13509836707

Tel: +86-769-89802722