Hot Work

Generally the term “hot work tool steels” refers to any tool steel which is able to perform in an environment 200˚C. Super imposed on the latter are peak temperatures brought about by the operation cycle. Consequently, the use of hot work tool steels implies, in addition to the usual stresses to which tool steels are subjected, a thermal stress due to contact between tools and hot materials during forming.

Hot work tool steels must exhibit good heat checking resistance in order to delay, for as long as possible, the formation of chill cracks appearing on the surface in a reticulate shape as a consequence of frequent temperature changes in the surface region.

To avoid hot cracks, i.e. tension cracks developing primarily in tools with deep cavities at sectional transitions and edges and extending deep into the tool (as opposed to chill cracks) , hot work tool steels also have to present good toughness. For tools subject to high impact, pressure or tensile stresses at elevated temperatures, special attention must be paid to high strength at the various working temperatures. If the structural state is changed by the influence of heat, strength at ambient temperatures and also strength at working temperatures are reduced. This is why high hot strength and superior retention of hardness are prerequisites of stability of shape.

Excellent hot wear resistance is necessary to guarantee sufficient tool life.

Further demands that must be met by hot work tool steels are low tendency to adhere to parts being processed, high resistance to erosion, high temperature corrosion and oxidation, dimensional stability in heat treatment, good machinability, and in some cases also good cold hobbing properties.

Böhler Steel

Only very special steels are suited to hot work applications. The particular properties of BÖHLER hot work tool steels are specifically trimmed to their use at high temperatures. The cleanliness of the steel is a deciding factor for a long tool life and for resistance to heat checking.

Typical applications for hot work tool steels are: pressure die casting, hot extrusion, open die forging, plastic processing and other hot applications.

If you are unable to find the material you require please check Uddeholm Grades.


 

W302 - 1.2344

5% Cr HOT WORK STEEL

COMPOSITION %

C

Si

Mn

Cr

Mo

Ni

V

W

Co

 

0.39

1.10

0.40

5.20

1.40

-

0.95

-

-

COLOUR CODE : W302 RED & GREEN (STRIPES) W302 ESR RED & GREEN (DOTTED)

PROPERTIES AND APPLICATIONS :

Excellent hot strength and wear resistance properties.
Highly stressed hot work tools, especially for working light metal alloys, such as
mandrels, dies and containers for tube rod extrusion, hot extrusion tools, tools and dies for the manufacture of hollow sections , nuts, bolts, rivets and screws, die – costing dies, mould dies, die inserts, hot shear blades and plastic moulds.

This material is also available in the W302 ESR (Electro Slag Remelted) condition, should improved production performance be required. Can be nitrided.


 

W303 – 1.2367

HOT WORK TOOL STEEL

COMPOSITION %

C

Si

Mn

Cr

Mo

Ni

V

W

Co

 

0.38

0.40

0.40

5.00

2.80

-

0.55

-

-

COLOUR CODE : RED & YELLOW

PROPERTIES AND APPLICATIONS :

Primarily used for the processing of light metal alloys.

Heavy duty hot work tools and dies, i.e. mandrels, dies and containers for metal tube and rod extrusions; hot extrusion equipment, tools and dies for the manufacture of hollow bodies, screws, rivets, nuts and bolts.
Die casting equipment, forming dies, die inserts, hot shear blades and plastic moulding dies


 

W320 – 1.2365

HOT WORK STEEL

COMPOSITION %

C

Si

Mn

Cr

Mo

Ni

V

W

Co

 

031

0.30

0.35

2.90

2.80

-

0.50

-

-

COLOUR CODE : RED & BLACK

PROPERTIES AND APPLICATIONS :

High hot strength & toughness, water cooling possible.
Highly stressed hot work tools, especially for processing heavy metal alloys, such as mandrels, dies and containers for tube and rod extrusions dies, tools for the manufacture of screws, nuts, bolts and rivets, die casting dies, mould dies, die inserts and hot shear blades.
This steel can also be nitrided


 

W360 ISOBLOC

HOT WORK STEEL

COMPOSITION %

C

Si

Mn

Cr

Mo

Ni

V

W

Co

 

0.50

0.20

0.25

4.50

3.00

-

0.60

-

-

COLOUR CODE : -

PROPERTIES AND APPLICATIONS :

W360 ISOBLOC was developed as a tool steel for dies and punches in warm and hot forging. This steel can be used for a variety of applications where hardness and toughness are required.
These applications include – tooling for high speed pressing, extrusion, die casting and plastic processing.


 

W500 – 1.2714

DIE BLOCK STEEL

COMPOSITION %

C

Si

Mn

Cr

Mo

Ni

V

W

Co

 

0.55

0.25

0.75

1.10

0.50

1.70-

0.10

-

-

COLOUR CODE : ANNEALED RED & WHITE

COLOUR CODE : HEAT TREATED ORANGE & WHITE

PROPERTIES AND APPLICATIONS :

Oil and air hardening steel with excellent toughness and through-hardening properties.
Dies of all sizes, extrusion and tube extrusion dies, hot shear blades, mould dies, bending and embossing tools.


Top

Uddeholm

The production base of Uddeholm is tool steel; however, our business idea is to sell and market tooling materials and services to tool makers, tool users, machine builders and their customers, providing the best total economy. Uddeholm have long experience in producing hot work tool steels for dies and extrusion tooling components. Uddeholm's extensive hot work tool steel range covers conventional and ESR melted grades and includes gades for die casting, extrusion tooling, forging, dies and other hot applications.

If you are unable to find the material you require please check Bohler Grades.

Title Type/Filesize Download

Orvar Supreme
An E.S.R melted Cr-Mo-V alloyed hot work steel with good high temperature strength and good resistance to abrasion.

PDF / 293 KB PDF Download

Alvar 14
A Cr-Mo-V alloyed hot work steel with good high temperature strength and good resistance to abrasion.

PDF / 137 KB PDF Download

QRO-90
A premium hot work die steel with high hot yield strength and good temper resistance. Especially suited for die casting of copper

PDF / 174 KB PDF Download

Hotvar
Hotvar is a premium hot work steel with very good high temperature properties. Can be hardened and tempered to 58HRC giving an outstanding hot wear resistance. Hotvar is particularly suitable for applications where hot wear and or plastic deformation are the dominating failure mechanisms.

PDF / 143 KB PDF Download

Dievar
An E.S.R melted high performance chromium-molybdenum-vanadium alloyed hot work tool steel which offers a very good resistance to heat checking, gross cracking, hot wear and plastic deformation.

PDF / 568 KB PDF Download

ESR



In Electro Slag Remelting (ESR) the ingot is built up in a water cooled mould by melting a consumable electrode immersed in a superheated process slag. An electrical current flowing through the liquid slag, which provides the electrical resistance, generates the heat. As the slag temperature rises above the liquids temperature of the steel, the tip of the electrode melts. The reaction between slag and steel droplets results in a significant reduction in sulphur and non-metallic inclusions. The directional solidification of the ingot from bottom to top results in an ingot with a high homogeneity and freedom from macro - segregations. This gives uniform mechanical properties in the longitudinal and transverse directions after hot working. By utilizing homogenisation annealing of ingots, a high ingot break down and special heat treatment methods for structure refinement and strategy is fulfilled in optimising steel properties for an extended tool life.

ESR melted and re-melted Grades Stocked

  • Uddeholm Orvar Supreme Listed above
  • Uddeholm Dievar Listed above
  • Uddeholm QRO 90 Listed above
  • Böhler W302 Listed above
  • Böhler W360 Isoblock Listed above

VMR

Vacuum Melted & Remelted: In order to obtain all the different properties specified, it is often necessary to combine various melting processes. (Internal Bohler description for Vacuum Arc Furnace is known as VAR)

Advantages

  • Optimum ingot structure.
  • Minimum gas contents.
  • Minimum content of trace elements ( such as As, Sb, Sn, Cu)
  • Highly uniform distribution of any remaining inclusions.
  • Optimum polishability.
  • Virtually isotropic properties.
    High reproducibility thanks to process automation.