A8 mod. / Chipper Steel

A8 is an air hardening 8% chromium tool steel. This steel is suited for applications which need the combination of high toughness and good wear resistance.

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Standard values
General Information

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A8 mod. / Chipper Tool Steel Standard values

Working hardness: 50 HRC - 60 HRC
Delivery condition: max. 250HB

Chemical composition in %

0.450000

0.45

–

0.500000

0.5

0.700000

0.7

–

0.900000

0.9

0.350000

0.35

–

0.450000

0.45

0.000000

–

0.020000

0.02

0.000000

–

0.005000

0.005

7.300000

7.3

–

7.800000

7.8

1.300000

1.3

–

1.500000

1.5

1.300000

1.3

–

1.500000

1.5

A8 mod. / Chipper Tool Steel Technical Properties

Very robust cold work steel which can be used for a wide range of applications. Has good through-hardenability and high toughness (reduced occurence of hard carbides with about 8% chromium compared to 12% chromium in AISI D2). High cutting power, high wear resistance as well as excellent tempering resistance.

A8 mod. / Chipper Tool Steel Applications

blanking tools, stamping tools, embossing tools, forming dies, press dies, die inserts, extrusion dies, reinforcements, cold extrusion tools, tube tools, cutting tools, industrial knives, wood chipping knives, veneer knives

Standard values

Chemical designation: Working hardness: 50 HRC - 60 HRC
Delivery condition: max. 250HB

Chemical composition:

0.450000

0.45

–

0.500000

0.5

0.700000

0.7

–

0.900000

0.9

0.350000

0.35

–

0.450000

0.45

0.000000

–

0.020000

0.02

0.000000

–

0.005000

0.005

7.300000

7.3

–

7.800000

7.8

1.300000

1.3

–

1.500000

1.5

1.300000

1.3

–

1.500000

1.5

Technical properties

Applications

A8 mod. / Chipper General Information

A8, also known as Chipper Knife steel, has a great combination of high toughness, good wear resistance and excellent dimensional stability during heat treatment. This steel grade is an excellent choice for applications like punches and dies as well as slitter knives, plastic granulator knives or tire shredding knives. In comparison to H13, A8 provides a better resistance to erosion, wear and wash-out for hot tooling applications.

Heat treatment

Annealing

After hot work and before re-hardening the material should be annealed. Heat the part no more than 400°F (222°C) per hours until a temperature of 1625°F (885°C), then hold the temperature 1 hour per inch (25.4 mm) of thickness but no less than 2 hours minimum. Cooling the material slowly in the furnace in steps of 20°F (10°C) per hour down to 1200°F(649°C), then continue to room temperature in the furnace or air.

Stress relieving

To relieve stress after rough machining, heat the work piece to a temperature of 1200°F (650°C) and hold for 2 hours. Finishing with a slow cooling in the furnace.

Hardening

Preheating slowly, first to 752°F (400°C), then to 1202°F (650°C), further to 1562°C (850°C) and then continue to the austenitizing temperature of 1886-1958 (1030-1070°C) in the furnace or in salt and soak for 30 minutes for the first inch (25.4 mm) of thickness and 15 minutes for any further inch (25.4 mm) of thickness.

Quenching media

To avoid thermal stresses, size alteration and/or distortion it is recommended to use the softest quenching medium possible. Quench immediately after hardening when the parts have reached a temperature of 176°F (80°C) with the exception of hot bath quenching (see temperature below).

Hot bath (workpiece cooled down to approx. 1022°F (550°C))
Air
Pressure gas
Oil, quench until black at approx. 900°F (482°C), then cool to 150-125°F (66-51°C) in still air

Tempering

A2 work pieces should be tempered immediately after quenching at a temperature range of 300-600°F (149-316°C). Hold for 1 hour per inch (25.4 mm) of thickness, but a minimum of 2 hours and cool in air to room temperature. To double temper any work pieces use a temperature of 900°F (483°C) and over. For material used for EDM or with a greater cross section of 6 inches (152.4 mm) a soaking time of 4-6 hours is strongly recommended.

For our tempering diagram, please click here.

Sub-zero treatment

While some people prefer cold austenitizing, others prefer cold treatment after tempering.

Machinability

Forging

Slowly heat the parts to a temperature of 1202-1256°F (650-680°C) and then increase the temperature uniformly to 1922-2120°F (1050-1100°C). Forging should be done above the temperature of 1832°F (1000°C) but never drop below 1652°F (900°C). Work pieces should be cooled slowly to avoid possible cracking.

Disclaimer

The data shown here has been compiled with the greatest diligence and is regularly updated with regard to the correctness and completeness of its content. The content is indicative only and should not be taken as a warranty of specific properties of the product described or a warranty of suitability for a particular purpose. All information presented is given in good faith and no liability will be accepted for actions taken by third parties in reliance on this information. ABRAMS Industries reserves the right to change or amend the information given here in full or parts without prior notice.