What We Offer

Case Harden

We Carburise and Carbonitride by the gaseous method, using computer controlled sealed-quench furnaces. Extremely tight control of carbon concentration, diffusion rates and temperature are required to process a component with minimum distortion and achieve optimum mechanical properties. The controlled atmosphere sealed-quench furnace is the most proven and respected method of producing high quality carburizing and carbonitriding. We offer carburizing depths of 0.1 - 3.5mm and we Carbonitride special processes to heat treat plain carbon and mild steel to a case depth of 0.1 - 0.8mm with minimal distortion.

In this process, steel is heated in the presence of a carbon environment. Due to this, carbon atoms are deposited into the metal surface to make it hard.

 

Case Hardening or Surface Hardening

 

The main aim of this process is to make only the external surface of steel hard, while the core hardness remains ductile and malleable. It is the process of carburization i.e., saturating the surface layer of steel with carbon.

Carburizing is a process used to introduce a surface case by exposing the metal to a carbon-rich environment at high temperatures (approximately 790 to 950°C, depending on the process). Following the heating process, the metal is quenched, locking the carbon in the crystal structure. Carburizing is a diffusion-controlled process, so the longer the metal is exposed to a high carbon environment, the more carbon will penetrate and diffuse into the structure.

Gas carburizing involves heating metal in a furnace in the presence of methane and propane along with neutral carrier gases. The neutral carrier gas have the role of controlling and increasing the amount of carbon available in the atmosphere. At high temperatures, the methane or propane decomposes into carbon and hydrogen at the surface of the metal, resulting in carbon diffusing into the surface. Gas carburizing can range from 10 hours to 45 hours, resulting in case depths of approximately 0.80 - 3.50 mm. This process is used to create a hardened case for gears.

  • To obtain a hard wear resistant surface on machined parts.

  • To obtains a tough core.

  • To obtain a higher fatigue limit and high mechanical properties in the core.

Maximum Sizes & Capacity

Our maximum furnace dimensions are broken down into two types:- 

 

Type A (maximum width furnace):

  • Widest - 880 mm 

  • Highest - 460 mm

  • Length - 1,000 mm

 

Type B (maximum height furnace):

  • Widest - 860mm 

  • Highest - 650 mm

  • Length - 1,000 mm

 

Distortion can be minimized up to 650 mm as these items can be stood upright in a Type B furnace. Items of up to 1,000 mm can be laid down flat and packed to minimize distortion, but no guarantee can be given on these items.

 

Maximum weight is consistent for a Type A and Type B furnace: 250 KG - 800 KG

Allow 2 - 5 days, however extraordinarily large jobs, components and/or case depths may take longer.

 

Urgent work is subject to load size and discussion with our Customer Liasion Department.

Carbonitriding is a heat treatment process used to increase the surface hardness of a metal, thereby reducing wear. During the process, atoms of carbon and nitrogen diffuse interstitially into the metal, creating barriers to slip, increasing the hardness and modulus near the surface. Carbonitriding is often applied to inexpensive, easily machined low carbon steel to impart the surface properties of more expensive and difficult to work grades of steel. The surface hardness of a carbonitrided part ranges from 55 - 62 HRC. Carbonitriding forms a hard, wear-resistant case and is typically 0.1 - 0.8 mm deep.

Carbonitriding is similar to gas carburization with the addition of ammonia to the carburizing atmosphere, providing a source of nitrogen. Nitrogen is absorbed at the surface and diffuses into the workpiece along with carbon. Carbonitriding done at 850 °C, is carried out at temperatures substantially higher than plain nitriding done at 530 °C but slightly lower than those used for carburizing done at around 950 °C. Carbonitriding tends to be more economical than carburizing and also reduces distortion during quenching.

  • To obtain a hard and wear resistance to machine parts of Mild Steels and low carbon steels.

Maximum Sizes & Capacity

Our maximum furnace dimensions are broken down into two types:- 

 

Type A (maximum width furnace):

  • Widest - 880 mm 

  • Highest - 460 mm

  • Length - 1,000 mm

 

Type B (maximum height furnace):

  • Widest - 860mm 

  • Highest - 650 mm

  • Length - 1,000 mm

 

Distortion can be minimized up to 650 mm as these items can be stood upright in a Type B furnace. Items of up to 1,000 mm can be laid down flat and packed to minimize distortion, but no guarantee can be given on these items.

 

Maximum weight is consistent for a Type A and Type B furnace: 250 KG - 800 KG

Allow 3 days, however extraordinarily large jobs, components and/or case depths may take longer.

 

Urgent work is subject to load size and discussion with our Customer Liasion Department.

Historically as above on carbonitriding, Mild Steels and plain carbon steel cannot be carbonitrided to depths greater than 0.80 mm. Based on this P.H. Heat Treatment has developed the Lamda Processes which allow us to harden Mild Steels and plain carbon steels to depths of up to 3.00 mm. The process is quenched in oil and a hardness of 55 – 62 Hrc can be achieved with minimal distortion.

 

Processes offered

Lamda 40 – 1.00 mm

Lamda 50 – 1.25 mm

Lamda 60 – 1.50 mm

Lamda 70 – 1.75 mm

Lamda 80 – 2.00 mm

Lamda 90 – 2.25 mm

Lamda 100 – 2.50 mm

Lamda 110 – 2.75 mm

Lamda 120 - 3.00 mm

Maximum Sizes & Capacity

Our maximum furnace dimensions are broken down into two types:- 

 

Type A (maximum width furnace):

  • Widest - 880 mm 

  • Highest - 460 mm

  • Length - 1,000 mm

 

Type B (maximum height furnace):

  • Widest - 860mm 

  • Highest - 650 mm

  • Length - 1,000 mm

 

Distortion can be minimized up to 650 mm as these items can be stood upright in a Type B furnace. Items of up to 1,000 mm can be laid down flat and packed to minimize distortion, but no guarantee can be given on these items.

 

Maximum weight is consistent for a Type A and Type B furnace: 250 KG - 800 KG

Allow 2 - 5 days, however extraordinarily large jobs, components and/or case depths may take longer.

 

Urgent work is subject to load size and discussion with our Customer Liasion Department.