Cold work tool steels are employed for the manufacture of tools for applications involving surface temperatures of not more than 200°C.
In this temperature range, they must feature the following properties in order to guarantee tool resistance to the high stresses arising from the numerous machining and shaping procedures.
Superior hardness
High wear resistance
Good toughness
Excellent compressive and impact strength
High dimensional stability in heat treatment
Sufficient mach inability
A well balanced alloy content ensures that optimum properties are achieved for individual applications.
GRAND/
BOHLER
Chemical composition ( average% )
Standards
C
Si
Mn
Cr
Mo
V
W
Others
DIN
AISI
JIS
K105
1.6
0.35
0.30
11.5
0.6
0.5
0.5
--
1.2601
X165CrMoV12
D2
SKD11
K329
0.52
0.95
0.4
8
1.4
0.45
--
--
--
A2
--
K340
1.1
0.9
0.4
8.3
2.1
0.5
--
Al 1.1
Nb 0.13
--
--
--
S600
0.9
--
--
4.1
5.0
1.8
6.4
--
1.3554
M2
SKH51
K-360
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K105
Properties
High carbon, high chromium (12%Cr) steel with minimum dimensional change. Particularly suitable for air hardening. Good thoughness.
Application
High-duty cutting tools (dies and punches), blanking and punching tools, woodworking tools, shear blades for cutting light-gauge material, thread rolling tools, tools for drawing deep drawing and cold extrusion, pressing tools for the ceramics and pharmaceutical industries, cold rolls (working rolls) for multiple- roll stands, measuring instruments and gauges, small moulds for the plastic industry where excellent wear resistance is required.
Heat treatment information
Heat treatment
Hot forming
forging
1050 to 850°C
Slow cooling in furnace or thermo insulating material.
Annealing
800 to 850°C
Slow controlled cooling in furnace at a rate of 10 to 20 °C/ hr down to approx. 600°C, further cooling in air. Hardness after annealing: max. 250 HB
Stress relieving
650 to 700°C
Slow cooling in furnace; intended to relieve stresses set up by extensive machining, or in complex shapes. After through heating, hold in neutral atmosphere for 1-2 hours.
Hardening
980 to 1010°C
Oil, salt bath (220 to 250°C or 400 to 450°C), air blast, still air.
Tools of intricate shape or with sharp edges should preferably be hardened in air or salt bath.
Holding time after temperature equalization:15 to 30 minutes.
Obtainable hardness: 64-66 HRC
Tempering
Slow heating to tempering temperature immediately after hardening/time in furnace 1 hour for each 20mm of workpiece thickness but at least 2 hours/cooling in air.
For average hardness figures to be obtained please refer to the tempering chart.
For certain cases we recommend to reduce tempering temperature and increase holding time.
Cold work tool steel with excellent toughness and good wear resistance.
Application
High duty machine knives for the cellulose, paper and fiber board industries. Flat and circular shear blades for plates up to 15mm thinkness.
Heat treatment information
Heat treatment
Hot forming
forging
1050 to 850°C
Slow cooling in furnace or thermo insulating material.
Annealing
800 to 850°C
Slow controlled cooling in furnace at a rate of 10 to 20°C / hr down to approx. 600°C , further cooling in air. Hardness after annealing: max. 240HB
Stress relieving
650 to 700°C
Slow cooling in furnace ; intended to relieve stresses set up by entensive machining, or in complex shapes. After thorough heating, hold in neutral atmosphere for 1-2 hours.
Hardening
1000 to 1020°C / Oil, salt bath(400 to 450°C )
1020 to 1040°C / Air
Holding time at hardening temperature: 15 to 30 minutes.
Obtainable hardness: 63-65 HRC Oil and salt bath hardening, 60-62 HRC air hardening.
Tempering
Slow cooling to tempering temperature immediately after hardening/ time in furnace 1 hour for each 20mm of workpiece thickness but at least 2 hours/ cooling in air.
Cold work tool steel with excellent air hardening properties, good dimensional stability, good toughness, high compression strength and wear resistance.
Very good retention of hardness, excellent electrical discharge machining properties.
Excellent bath, gas, plasma nitriding and PVD-coating properties.
Good vacuum hardening properties. Through the chemical composition uniform distribution and smaller carbide size than high chromium steels.
Better toughness and electric discharge mach inability.
Application
Cutting tools (dies and punches), blanking and punching tools
Cold forming tools
e.g. drawing, deep drawing and extrusion tools, coining tools, thread rolling dies
Shear blades
Measuring tools
Woodworking tools
Advantages
High retention of hardness (higher than 1.2379) also at long times, very good suitable for surface treatment, e.g. bath, gas nitriding and PVD-coating
High toughness up to 45J, approx. 3x higher than 1.2379 (dependent upop hardening and tempering temperatures)
High compression strength(0.2%-compressive strength) over up to 3000N/mm 2 (corresponding 1.2379)
High dimensional stability -0.15/+0.15%
Good wear resistance, especially when subjected to combined adhesive and abrasive friction
Very good electrical discharge machining properties
Arithmetical average roughness 20 to 30% lower than high carbon, high chromium(12%) steel.
Heat treatment information
Heat treatment
Hot forming
Forging
1050 to 850°C
Slow cooling in furnace or thermo insulating material.
Annealing
800 to 850°C
Slow controlled cooling in furnace at a rate of 10 to 20°C/hr down to approx. 600°C, further cooling in air.
Hardness after annealing max. 250HB
Stress relieving
approx. 650°C
Slow cooling in furnace; intended to relieve stresses set up by extensive machining, or in complex shapes.
After through heating, hold in neutral atmosphere for 1-2 hours.
Hardening
1040 to 1080°C
Oil, salt bath, compressed air, air
After through soaking, hold for 15 to 30 minutes.
Obtainable hardness:61~63 HRC
Tempering
Slow heating to tempering temperature immediately after hardening/ time in furnace 1 hour for each 20mm of workpiece thickness but at least 2 hours/ cooling in air.
1100-900°C/ slow cooling in furnace or in thermo insulating material.
Annealing
770-840°C/ slow cooling in furnace. Hardness after annealing: max. 280 Brinell
Stress relieving
600-650°C/ slow cooling in furnace. To relieve stresses set up by extensive machining or in tools of intricate shape. After thorough heating, hold in neutral atmosphere for 1-2hours.
Hardening
1190-1230°C/ Oil, salt bath(500-550°C), dry air blast. Upper temperature range for parts of simple shape, lower for parts of complex shape.
Holding at hardening temperature: Salt bath hardening involves the term "immersion period" which is to be understood as the time from placing the parts into the bath, until they are removed. The immersion period is composed of the heating up time, i.e. the time it takes to heat the part from the last preheat stage to hardening temperature, and of the soaking time proper.
Soaking time is the time at hardening temperature which, after thorough heating, is required for dissolving sufficient carbides to obtain a favorable austenite percentage. Heating up period and, consequently, soaking time, depend on the cross section of the workpiece.
Tempering
Slow heating to tempering temperature immediately after hardening/ time in furnace: 1 hour for every 20mm of workpiece thickness, but not less than 2 hours/ air cooling (minimum holding time: 1 hour)
1 st tempering to maximum secondary hardness.
2 nd tempering to desired working hardness: average obtainable hardness values are shown in the tempering chart.
3 rd tempering for stress relief, 30-50°C below highest tempering temperature.
Nitriding
Parts made from this steel can be bath- gas- and plasmanitrided.