Ground Flat Stock - Applications

The tool steel GFS pieces (O-1, A-2, D-2, H-13, S-7, and W-1) are usually machined in the annealed state and then heat treated to make hardened, long lasting tools. The corrosion-resistant stainless steel GFS pieces (410, 420, and 440C) are also annealed and heat treatable. The pre-hardened GFS pieces (4142) can be machined even though they are already hardened. The low-carbon GFS pieces (C-1018) can be cold formed, bent, brazed, or case hardened.

The Applications Table below lists the classes, steel grades, hardening methods and typical applications of ground flat stock. To use the table, find the class in the left column. Read the steel grade, hardening method and typical applications in the other columns of the same row.

Class Steel Grade Hardening Method Typical Applications
Most Popular O-1 Oil Quenched Machine ways
Shear blades
Forming dies
Blanking dies
Shearing and trimming dies
Lowest Cost(Cold Drawn) W-1 Water Quenched Cold heading tools
Hand-operated tools
Metal cutting tools
Embossing taps
Keyway keys
Wear Resistance A-2
Air Quenched Knurls
Cold-forming tools
Piercing dies
Blanking dies
Coining dies
High Speed M-2 Vacuum Heat Treatment Cutting tools
Hot-work tools
Lathe tools
Woodworking tools
High Temperature H-13 Air Quenched Hot-work tools
Die-casting tools
Polished plastic mold tools
Hot shear blades
Forging dies
Corrosion Resistance 410420
Application Dependent Fasteners
Mold cavities
Surgical instruments
Low-Carbon C-1018 Carburize Backing plates
Machine parts


O-1 Ground Flat Stock may be the most popular grade and can be used for machine ways, gages, shear blades, and dies for forming, blanking, shearing trimming, etc. W-1 flat stock is the least expensive and can be used for making cold heading tools, hand-operated metal cutting tools, reamers, embossing taps, keyway keys, and shims. W-1 is not precision ground. It is cold drawn instead. It is similar to drill rod. But the shape is rectangular, not round like ordinary drill rod, so the pieces are categorized with GFS.

A-2, A-6, or D-2 GFS is used for knurls, rolls, hobs, knives, cold-forming tools, and dies for piercing, blanking, or coining. Compared to A-2, A-6 has lower hardening and tempering temperatures that result in less distortion. It has lower hardness and machinability. D-2 has greater wear resistance but is more susceptible to shock. It is also more difficult to machine and grind.

M-2 GFS is an excellent choice for making high-speed cutting tools or parts that must retain hardness at elevated temperature. It can be used for hot-work tools, broaches, hobs, chasers, reamers, lathe tools, saws, punches, and woodworking tools.

H-13 GFS is another good choice for hot-work tools and it has better shock resistance than M-2 GFS. It can also tolerate water cooling in operation. A nitride coating will increase hardness. It can be used for die-casting tools, polished plastic mold tools, hot shear blades, and forging dies.

S-7 GFS is extremely resistant to shock and can be used for making chisels, screw driver blades, circular pipe cutters, shear blades, pins, punches, and stamps.

The 410, 420, and 440C stainless steels are very popular for their corrosion resistance, hardness, and toughness. 410 GFS can be used for fasteners, valves, and shafts.  420 GFS is harder than 410 and responds better to polishing. It can be used for plastic injection mold cavities, knives, shafts, and surgical instruments. 440C GFS is extremely hard when heat treated which enable the manufacture of high quality cutlery, bearings, surgical instruments, and chisels.

4142 GFS is also known as “chrome moly”. It has exceptional resistance to fatigue, abrasion, and impact. It can be used to fabricate crankshafts, gears, retainer plates, axels, and shafts.

C-1018 GFS has the lowest hardness of all the ground flat stocks but it can be carburized or case-hardened. It is easy to cold form, bend, or braze and its magnesium provides greater strength and hardness than many other carbon steels. It can be used for making backing plates, risers, stops, and machine parts.