Hardening & Tempering Heat Treatment

Bluewater Thermal Solutions' hardening and temper hardening heat treatment solutions enlist a wide variety of techniques designed to increase the hardness, strength, and fatigue life of metal parts and components.

Learn More About Our Processes:


Neutral Hardening Equipment Options

  • Batch furnaces with oil quench
  • Continuous mesh belt or roller hearth furnaces with oil or water quench
  • Saltpot furnaces with water or marquenching salt
  • Vacuum furnaces with high-pressure gas quench

Open Fire Hardening Options

  • Carbottom furnaces with water or polymer quench
Our Unique Advantages
  • Our equipment provides the ability to handle both large and small orders.
  • Continuous mesh belt furnaces are available for processing large volumes of small parts such as fasteners, bearings, stampings, and washers at competitive rates.
  • We specialize in hardening large castings and forgings using atmosphere-controlled continuous furnaces that prevent decarburization and scaling.
  • Our continuous furnaces provide lowest cost hardening.   
  • Prevention of scaling eliminates the need for blasting to clean parts and remove scale after heat treatment, which can be very costly.
  • We specialize in the hardening of long bars, tubes and plates up to 24’ length.
  • Our in-house laboratory provides tensile and charpy testing after hardening for a quick turnaround.
  • Hot oil quenching and hot salt mar quenching are utilized to minimize warpage on distortion-prone parts.   
  • We have equipment specifically designed to handle the unique challenges associated with heat treating powdered metals.
  • Our unique multi-plant capability to perform hardening in multiple locations provides built-in emergency backup and contingency planning.
What Is Hardening and Tempering Steel?

The hardening of steels and irons involves heating a material to a temperature above its austenitizing temperature, which converts the material structure to austenite. After the material has been fully transformed to austenite, it is rapidly quenched to transform the material structure to martensite which increases the hardness and strength of the material to its highest possible level. After quenching, the material is tempered down to the desired final hardness and strength level by re-heating to a lower sub-critical temperature which serves to substantially increase ductility and toughness as the hardness and strength are gradually reduced.

Neutral hardening is performed in a neutral atmosphere where there is no net gain or loss of carbon, nitrogen or other elements to the material’s surface. This is typically used for finished or near-finished parts where decarburization of the surface is not allowed.

Open fire hardening is performed in air atmosphere furnaces where carbon can exit the material’s surface by reacting with air causing surface decarburization to occur. This is often performed on raw materials or rough parts where all surfaces will be ground or machined after hardening, which will remove the decarburized surface layer.

This process is also commonly referred to as quench and temper, harden and temper, and through hardening.

Properties and Areas of Application of Hardened Stainless Steel

Hardened stainless steel used in fields of application, where high demands are placed on corrosion resistance and wear protection. We produce a surface which is up to 5 times harder and moves the operating limits of the previously soft steel.

The areas of application are varied and comprise the consumer goods and household goods sector, mechanical engineering and construction, medical technology, automotive and components industry.

Several different methods and types of equipment can be selected for neutral hardening. The processing parameters, atmospheres used, and particular furnace type is chosen based on the particular steel or iron grade requiring hardening and if the quantity of parts to be treated is an individual piece, small lot, or a high volume production order.


Bluewater performs heat treatment of stampings and fineblankings for a variety of different equipment. Capable of handling both large and small stamping and fineblanking projects, Bluewater uses batch furnaces as well as continuous mesh belt furnaces to ensure the quality and size of the amount are never compromised.

Carburizing, Carbonitriding, Hardening, and Ferritic Nitrocarburizing for Stampings and Fineblankings

Most stampings and fineblankings are plain carbon or alloy steel and require processes such as carburizingcarbonitriding, hardening or ferritic nitrocarburizing (FNC). Hot oil quenching and marquenching salts are available at some Bluewater locations to further assist in preventing stampings and fineblankings from distorting during quenching.

Bluewater specializes in heat treating stampings and fineblankings used in seating components along with clutches and transmissions for vehicles.

Bluewater has laboratories capable of inspecting stampings and fineblankings for surface hardness, core hardness, and case depth for case hardening processes after heat treatment.

About The Process:

Batch furnaces are used to heat treat larger stampings that require individual vertical racking to prevent distortion and warping. These parts often have flatness requirements, and methods such as clamp tempering and slide gage sorting are routinely performed. Continuous mesh belt furnaces are utilized for smaller stampings that are not distortion prone and can be heat treated in bulk. Automated loading systems ensure uniform loading of belts and proper metallurgical requirements for each part. Belt processing is the most cost-effective way to heat treat stampings and fineblankings, requiring minimal labor and processing high volume quantities efficiently.


Bluewater specializes in heat treating fasteners with controlled loading using dedicated racks or automated loading systems for consistent heating and quenching. Statistical capability studies are conducted over time, and all locations have a metallurgical laboratory to inspect surface hardness, core hardness, case depth, and microstructure.

Bluewater is capable of performing breaking torque, bend testing, and drill-drive testing of fasteners.

About the Heat Treatment Process

Bluewater has continuous mesh belt furnaces at several locations for bulk heat treatment of small fasteners. Fasteners that are 6” or longer are hung vertically in racks and processed in batch furnaces to maintain better straightness down the length of a screw. Carburizing, carbonitriding and neutral hardening are all performed on various different types of screws, bolts, washers, nuts, and nails made from plain carbon and alloy steels. Vacuum hardening and passivation of stainless steel fasteners is also performed at some locations. 


Bluewater Thermal Solutions' facilities in St. Mary's and Ridgway, Pennsylvania are strategically located to serve the powdered metal industry. As the leading commercial heat treatment provider to this industry, we use the latest technology and equipment to deliver high-quality, precise heat treatment to powder metal components. With years of expertise in the field, we continuously advance our process, quality control standards, and exceed customer expectations, big or small.


Bluewater performs tool steel and stainless steel heat treatments in vacuum furnaces at several facilities. Many grades of tool steel, high alloy steels, and stainless steel have the ability to be heat-treated using a high-pressure nitrogen gas quench instead of requiring a liquid quench. This allows these materials to be heat-treated in a vacuum furnace rather than using an atmosphere furnace with liquid quench tanks.

Heating in a vacuum where all gases including oxygen have been removed allows the material to be heated without oxidation, scale formation or other reactions such as carburizing, decarburizing, nitriding, and de-alloying occurring.

IMG_0223.JPGMaterials can be heated without oxidation, scale formation, or other reactions such as carburizing, decarburizing, nitriding, and de-alloying by heating in a vacuum where all gases, including oxygen, have been removed. Tool steels and stainless steels undergo this process before being quenched in high-pressure inert nitrogen gas to enable rapid cooling, maintaining the material's bright and shiny surface. Gas quenching instead of liquid quenching reduces distortion and minimizes size change, making Bluewater's vacuum heat treatment services on these grades with nitrogen or vacuum tempering ideal. Cryogenic treatment is also recommended and performed on some tool steels and stainless steels.


Bluewater Thermal Solutions processes a variety of metal components and provides heat treating services including processing, coating, and metal joining at processing plants across North America. Aerospace heat treatment processing is performed with strict adherence to the industry specifications required for each component treated.

Our South Bend, Indiana location has NADCAP accreditation to perform heat treatment for the aerospace industry.


Industrial Heat Treating Overview
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