We have already told you a great deal about various stainless steel alloys and about steel in general - our articles on cold-rolled steel and cutting stainless steel are examples. But our knowledge is far from exhausted. This time, we want to inform you about hot work steel. What is it all about? Where do you encounter 1.2343 hot work steel in everyday life?
Our examples of hot work steel will show you that it is a material we use quite naturally in many places. It comprises alloyed tool steels that can be used at higher surface temperatures - which is precisely the decisive difference between cold work steel and hot work steel.
Hot work steel can be used at surface temperatures of up to 400° Celsius. For cold work steel, the ceiling lies at a temperature of 200° Celsius. If even higher surface temperatures occur when using the tool, high-speed steel is available as a tool material up to a value of 600° Celsius. The melting point of hot work steel is not reached in normal use.
Hot work steel properties
The material properties of hot work steel are ideal for use as a tool at high temperatures. Hardening and repeated tempering enhance its hot strength. Alongside hot strength, hot work steel is also characterised by hot toughness.
It has good thermal conductivity and high resistance to hot cracking. Tempering resistance and creep strength are further characteristics of hot work steel. These properties are made possible by an alloy that, besides carbon, may contain chromium, silicon, tungsten, nickel, molybdenum, manganese, cobalt and vanadium.
Hot work steels are most often found as the material of dies in drop forges. It is also used as tooling for die casting and extrusion, and many injection moulds are likewise made of hot work steel. Even though we ourselves rarely come into direct contact with this steel, it has a great influence on products of our daily lives.
How hot work steel is processed
It is a steel that can be worked well in various ways. It etches very well and has good polishing properties. Spark erosion is carried out in the hardened state at approx. 20° Celsius below the last tempering temperature. Nitriding can increase resistance to wear and prevent casting material from sticking.
In use, heat treatment is of great importance, because it can increase surface hardness. So let us go into this below.
Hardening
Hardening requires a temperature range between 1,000 and 1,040° Celsius. This temperature, also called the hardening temperature, must be held for at least 15 minutes and at most 30 minutes. Air is sufficient for quenching; alternatively, water or oil can be used. A hardness of 50 to 56 HRC is achieved.
Soft annealing
This is a lengthy process. Hot work steel must be held at a temperature of 750 to 800° Celsius for a period of 4 to 5 hours. The workpiece must then cool slowly in the furnace: as a rule of thumb, cooling by 10 to 20° Celsius per hour until a temperature of 600° Celsius is reached. It can then cool further in the air.
Nitriding
As a preparatory step before nitriding, stress-relief annealing at 550° Celsius should be carried out. Subsequent treatment with ammonia gas at a temperature of 525° Celsius can achieve a surface hardness of 55 HRC.
Tempering
To improve hardening, it is recommended to warm the workpiece slowly in the furnace directly after hardening. As a rule of thumb, one hour in the furnace per 20 mm of workpiece thickness. Repeated tempering intensifies the effect.
Are you looking for hot work steel?
It actually makes no difference which type of steel or stainless steel you need - you will quickly discover that it is by no means common merchandise. You will have to turn to specialist companies if you need sheets in a specific dimension. Even if you are skilled with your hands and confident about cutting stainless steel yourself, you will first have to clear the hurdle of purchasing.
We recognised this many years ago and aligned our company with our customers' needs. It is by no means only large companies that need individual sheets. That is why we have developed into a service provider for stainless steel and can accept large and small orders alike - we work for private customers just as gladly as for major buyers.
We work exclusively to customer order
Since we offer no off-the-shelf product, we manufacture every sheet to customer order. Our employees and machines are so flexible that our average production time is under 48 hours - meaning the product you order from us is handed over for dispatch within two days of your order.
To keep to that, we constantly maintain a huge stock of sheets - generally a good 2,000 tonnes of stainless steel sheets in various alloys and thicknesses. These are naturally the steel grades our customers order frequently, and all sheets come from European production. Should you have a special request, we can fulfil it with a little lead time - for example, a steel sheet in a foreign standard.
We advise you without obligation
Every order passes through our sales team, so we can ensure you receive the optimum sheet for your intended use. Our experienced staff can determine with a few questions which alloy is best suited to you. The various alloys differ greatly: we stock several grades of heat-resistant steel, while other steel grades are not suited to high temperatures.
During this short phone call, we can also quote you the price for your made-to-measure sheet immediately - here too we are fast, because we sell many individual products every day. With us, you do not have to wait for a quotation. If you then decide to order, we put your job into production immediately. After just a few working days, you hold a made-to-measure sheet in the right size and shape in your hands. The installation, however, is then up to you.
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