Manufacturing Services of Cold Heading Bolts at JM Hardware®

Steps for producing Cold heading bolts

Cold heading is done by a variety of cold heading machines. It involves moving metal through a series of dies to form the part to its desired shape.

Cold heading machines use a coil of wire and form the wire into desired parts at very high rates of speed allowing the cold-headed parts to be made very quickly and economically. The process begins by loading a large coil of wire in front of the cold heading machine.  The wire is purchased in a condition called spherodized anneal. This special condition allows the material to be formed without cracking.

The wire is then pulled through a wire draw box to change the stock diameter to the specific diameter required to manufacture the fastener. Running the wire through a draw box makes the wire shape very round with a tolerance of .001. This is very important to holding size on the final parts after it is cold headed. A wire straightener can also be added which will align the wire prior to going into the cold heading machine. Straightening the wire is especially important on long parts.

After the wire has been successfully drawn to size, the wire enters the inside of the cold heading machine.  The wire goes through a cut-off die and continues until it reaches a wire-stop.  Once it reaches the wire stop, a cut-off knife moves across the wire, cutting it off to a specific length.  This is referred to as the cut-off slug.

The specific steps of cold heading process at  JM Hardware®

Step1：Find quality raw materials

Raw materials refer to the raw materials purchased from manufacturers, which mainly include the following parameters:

A. Brand

B. product name

C. Specifications

D. Material                                                                         

E. Heat number or batch number                                      

F. Number/weight

                                                      Round  raw material at JM Hardware® factory

Step2：Wire drawing/Phosphating

Function

Wire drawing:

1. Rust removal

2. Pull until the specified wire diameter

Phosphating:

Smooth material surface to reduce damage to machine

                                                        Wire drawing/Phosphating at JM Hardware® factory

Step3：Cold heading

This  contains head forming, punch marking,Reducing rod, chamfering, cutting off In one

                                            Multifunctional cold heading machine at JM Hardware® factory

Step4：Thread  Rolling

The thread rolling uses two plate-like tools with inclined teeth to move toward each other to squeeze the workpiece, forming threads on the surface of the workpiece.

Step5: Heat treatment (not necessary)

Heat treatment is a thermal process that accomplishes three primary improvements to the material properties of metal castings:

Improving mechanical properties.

Enhancing corrosion resistance.

Reducing residual stresses.

                                                             Heat treatment production line at JM Hardware® factory

Step6:  Surface treatment

The surface treatment of fasteners is a process of forming a covering layer on the surface of the workpiece by a certain method, 

and its purpose is to endow the surface of the product with beautiful and anti-corrosion effects.

                             plain (before)                                                                                             Blcak（after）

Step7:  Sampling test

For the finished bolts, JM Hardware® will conduct sampling inspection to ensure the quality of our products

Step8:  Package

JM Hardware® offers a variety of packaging options to ensure that products are delivered to customers intact. 

Or you can also inform us of your packing requirements, we will do our best to meet your requirements

Step9:  Transportation

JM Hardware® will carry out the most suitable shipping according to the trade method you choose

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