Alloys for Tool Steels

Tool and die welding refers to the repair and manufacture of metal parts that change the shape of other metals or materials. The nature of its job dictates that tool steel must be capable of cutting, stamping, drawing, punching or in some way changing the shape of other metals without itself becoming worn or distorted. According to the type of tool steel we are referring to, it will have certain characteristics that make it special and different from other tool steels. The Society of Automotive Engineers (SAE) and the American Iron and Steel Institute (AISI), Tool Steel designations are self explanatory as to the function of that particular steel.

Tool Steel Designations AISI SAE

W1 Thru W5 Water Hardening
01 Thru 06 Oil Hardening
A2 Thru A10 Air Hardening
M1 Thru M47 High Speed
S1 Thru S7 Shock Resisting
L1 Thru L7 Special Purpose Steels for Die Blocks
P1 Thru P21 Mold Steels
D1 Thru D7 High Carbon; High Chromium
H10 Thru H43 Hot Work
T1 Thru T15 Tungsten High Speed


Most tool steels have the capability of being annealed (becoming soft). When the die or tool is made, it must be soft enough to be machined. After the part is made, it must be capable of being heat treated to bring it into the desired hardness range (hardness is explained in the wearfacing section). Shops that deal with Tool and Die work have a close association with heat treating. Terms such as anneal, temper, and harden should be understood in order to see how the manufacture or repair of a die is achieved.

Tool and die welding takes place when:

1. Dies have to be repaired
2. Correcting design changes
3. Manufacture composite dies
4. Fix mistakes

1. Repairing dies is a major part of tool and die welding. Parts that wear in certain areas, or chips that develop must be repaired as quickly as possible without having to completely rework the die by annealing and reheating. Filler alloys such as MG 700 and MG 710 can be deposited and in most cases subsequent heat treating is not necessary.

2. Correcting design changes as a die is being worked in or changed over could mean adding a small amount of metal or great amounts of metal such as on cutting edges. Tool steel welding will permit the addition of comparable metal at the desired points to salvage expensive tools or dies.

3. Manufacturing composite dies is becoming more popular because of companies trying to reduce costs of manufacture. Rather than make tools or dies completely from a particular type of expensive tool steel like 4130 or 4140. Then the parts that will be exposed to the cutting or stamping is built up using a suitable tool steel filler alloy.

4. Fixing Mistakes usually occurs at the machine shop level. If a part being repaired or fabricated is over-machined, compatible tool steel filler alloys must be applied to bring the part back up to tolerance.

MG Tool Steel alloys are most often used to repair or correct a design change or fix mistakes. The MG Tool Steels are hard as deposited or can be annealed to facilitate machining. MG 700 is basically a modified high speed tool steel compatible to most other tool steels. It is used where higher hardness is needed. MG 710 is a modified air hardening type tool steel also compatible to most other tool steels. It is used where very high hardness is not needed or when the part must be forged or annealed then re-heat treated.

A mistake often made by tool welders in repairing broken dies is using tool steel electrodes as a joining rod. When the broken tool is being put together using the tool steel electrode, the joint will become hard and brittle and not capable of taking impact. This is because the alloying elements in this type of electrode make the deposit hard throughout the joint area. The proper procedure would be to prepare the joint for welding, then use MG 600 to join the broken parts together. The joint should be built up to within three passes of the finished dimension. The appropriate tool steel electrode is then used to cap off the surface of the working area. MG 700 is used where high hardness is needed and MG 710 is used when medium high hardness is needed.
 

 

MG 700

High hardness alloy for most tool steels.
Specially formulated for use on high speed tool steels.
Moderate resistance to impact.
For uses such as: hot shears, trimming plates, dies, & lathe tools.

 

SDS

Data Sheet

 

 
 
MG 700 MIG

Same characteristics as the MG 700, but in a wire version

 

SDS

Data Sheet

 

 
 
MG 700 TIG

Same characteristics as the MG 700, but in a 36 cut length TIG version.

 

SDS

Data Sheet

 

 
 
MG 701 TIG

TIG wire for maraging & other tool steels. Contains nickel, cobalt & molybdenum.

 

SDS

Data Sheet

 

 
 
MG 710

Most universal alloy for high impact and high abrasion resistance.
Deposit is that of an air-hardening tool steel.
Excellent cold trimming characteristics.
Multiple passes can be made without cracks.



SDS


Data Sheet

 

 
 
MG 710 TIG

Same characteristics as the MG 710, but in a 36 cut length TIG version.

 

SDS

Data Sheet

 

 
 
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