Carburizing Services & Carbonitriding Services

Increase the surface hardness and wear resistance of metal parts

Carburizing is a case hardening process in which a metal part or component of low carbon content is heated in a carbon-rich gas atmosphere. This allows for diffusion of carbon atoms directly into the surface of the part that needs to be case hardened.

Higher temperatures, longer carburizing cycle times, and higher carbon potentials will increase the amount of carbon diffused into the surface and the depth of case. The hardening of both case and core material does not actually occur until the metal is rapidly quenched.

Bluewater's carburization service is designed to be efficient and yield the best possible final microstructure and mechanical properties.

After quenching, carburized parts are tempered down to meet the customer requirements for case and core hardness. Tempering dramatically improves ductility and toughness with a minor loss in hardness and strength.

Carburizing Properties
  • Increases surface hardness
  • Improves wear resistance and fatigue strength
  • The core of the material being hardened is tough and ductile
  • Case depths can be varied from .002″ to .250″ depending on application and intended use
  • Can be used on simple or complex parts
  • Can be performed in batch equipment for low to medium volume work or in continuous equipment for high volume work
  • Typically works best with low carbon and alloy steels with a carbon content between 0.05% to 0.30% C
  • Surface of parts should be clean and free of rust or scale
Carburizing Applications
  • Parts which require increased wear resistance and fatigue strength
  • Parts made from low carbon content steels



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 carburizing, carbonitriding, 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. Since these components are usually cost sensitive items to the automotive industry, Bluewater's technicians work with customers to determine the most economical solutions to perform heat treating of stampings and fineblankings.

About the Process

Heat treating in batch furnaces usually consists of racking parts on edge in baskets or hanging vertically on rods with spacers between the stampings and fineblankings to minimize distortion and warping. Many parts have flatness requirements and clamp tempering and slide gage sorting for flatness are available and performed routinely.

Heat treating in belt furnaces is performed using automated loading systems to create uniform loading of the belts and ensure each part meets all metallurgical requirements after processing. Belt processing is the most economical method to perform heat treatment of stampings and fineblankings as it requires minimal labor and high volume quantities may be efficiently processed in this manner.


Specializing in the heat treatment of fasteners, Bluewater designed their processes to have controlled loading using dedicated racks for batch furnaces or automated loading systems with metering equipment on belt furnaces to achieve consistent heating and quenching of all parts to ensure uniformity of results. Statistical capability studies are performed over time to monitor the processing parameters and results.

All Bluewater locations have a metallurgical laboratory for inspection of surface hardness, core hardness, case depth, and microstructure of fasteners.

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 provides heat treatment services for metal gears at our multi-state network of processing plants. Carburizing services, carbonitriding services, gas nitriding services, and hardening are the most common processes performed. Batch heat treating furnaces are typically employed with the gears being racked on custom fixturing to prevent any damage to the teeth and ensure uniform heat treating on all surfaces.

Bluewater also recommends and performs normalizing treatments to gear blanks or rough machined gears to remove any residual stresses prior to final machining and heat treatment in order to further reduce distortion and dimensional change.

Processing parameters are carefully chosen to meet hardness, case depth, and microstructural requirements. Gears are often inspected in multiple locations such as the gear tooth mid-pitch, root and tooth tip locations and often customers will require different specifications be met at each of those locations. Blasting is often performed after heat treatment to clean the gears prior to shipment back to the customer.


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
We provide a comprehensive list of services that can be combined to provide a perfect process for your components.
North America's thermal processing specialists are ready to serve you from our multiple locations.
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