Specific Black Oxide Equipment Suppliers for Investment Cast Stainless Parts

When manufacturing investment cast stainless steel parts, applying a black oxide finish is a popular way to provide corrosion resistance while giving the parts an attractive black matte appearance. However, finding the right equipment and service providers for black oxide finishing can be challenging.

In this article, we’ll look at some of the top suppliers of black oxide equipment and services specifically for investment cast stainless steel parts.

Black Oxide Process Overview

First, let’s briefly review the black oxide process. Black oxide, also known as blackening, is a chemical conversion coating that forms a layer of magnetite (Fe3O4) on the surface of ferrous metals like steel and cast iron. The magnetite provides excellent corrosion resistance and changes the color of the metal to an attractive black finish.

The main steps in black oxide finishing are:

• Cleaning – The parts are thoroughly cleaned to remove oils, scale, rust, etc.


• Blackening – The parts are immersed in a hot alkali salt solution which reacts with the iron to form magnetite.


• Rinsing – The parts are rinsed clean after blackening.


• Sealing – A sealant is applied to protect the black oxide coating.

Proper cleaning, temperature control, bath chemistry, and sealing are critical to achieve an even, durable black oxide finish on investment cast stainless parts.

Black Oxide Equipment Suppliers

There are a number of equipment manufacturers that supply turnkey black oxide lines designed specifically for stainless steel investment castings.

• Birchwood Technologies – Based in the USA, Birchwood is one of the leading suppliers of black oxide equipment and chemicals. They offer automated lines engineered for stainless steel parts with specialized filtration, precise temperature controls, and sequencing. Tanks are constructed of stainless steel.


• Gesswein – Another major USA manufacturer, Gesswein provides turnkey black oxide systems for all types of parts including stainless investment castings. They utilize PLC controls and can customize bath sizes and tank materials.


• Arbitrary Systems – An Indian equipment maker, Arbitrary Systems produces reasonably priced black oxide plants optimized for stainless steel castings. Lines feature PLC operation, automated hoists, and stainless steel tanks.


• Santec Exim – Based in India, Santec Exim manufactures affordable blackening equipment engineered for stainless steel castings. Systems include material handling, PLC controls, and stainless steel tanks.


• Sandalwood Engineering – Sandalwood Engineering is an Indian equipment builder specializing in black oxide systems for stainless steel investment cast parts. Lines incorporate material handling, temperature controls, and stainless tanks.

When selecting black oxide equipment, key factors to consider are the tank construction material, filtration systems, temperature control capabilities, automation level, and capacity to handle stainless castings.

Black Oxide Finishing Services

In addition to buying turnkey equipment, many manufacturers of stainless investment castings opt to outsource black oxide finishing to a specialized service provider. There are a number of benefits to utilizing a blackening service versus installing in-house equipment:

• No equipment purchase or maintenance costs


• Expertise in achieving proper black oxide quality on castings


• Flexibility in capacity – can handle varying production volumes


• Often more cost-effective for lower volumes

Here are some of the top black oxide finishing service providers for stainless steel investment castings:

• Astro Chemicals – With facilities in the USA and Europe, Astro Chemicals provides specialized black oxide finishing for stainless steel castings. They work with aerospace, medical, and other industries.


• Erie Plating Company – Located in Pennsylvania, USA, Erie Plating is a large-scale black oxide finishing service with expertise in stainless steel investment cast parts. They service diverse markets including aerospace, medical, and more.


• Hohman Plating – A leading USA blackening service provider, Hohman Plating provides black oxide finishing optimized for stainless castings. They offer a range of sealing options.


• Raghav Impex – Based in India, Raghav Impex specializes in black oxide finishing for stainless steel castings. They offer cost-effective services and global delivery.


• Swiss Black Ltd – Located in the UK, Swiss Black provides specialty blackening services for stainless steel investment cast parts. They service the aerospace, medical, dental, and industrial markets.

The best black oxide service providers for investment cast stainless parts have expertise in achieving high-quality, uniform black finishes on steel castings while meeting industry specifications.

Other Considerations for Black Oxide Castings

Here are a few other important points to consider when black oxide finishing investment cast stainless steel components:

• Part design – Parts should be designed to allow for complete draining and drying. Internal passages or blind holes can trap chemistry and affect results.


• Surface prep – Castings must be thoroughly cleaned and free of scale, fire staining, grease, etc. for blackening to be effective.


• Performance testing – Salt spray testing per ASTM B117 should be conducted to validate corrosion resistance.


• Specification conformance – Ensure black oxide coatings meet requirements of MIL-DTL-13924, AMS2700, etc.


• Sealing – The right sealant must be selected to protect the black oxide finish and prevent rub off during handling.

By partnering with a qualified black oxide equipment supplier and finisher, manufacturers can consistently achieve outstanding black oxide quality on stainless steel investment castings.

Applying a black oxide finish is a great way to improve the corrosion resistance and appearance of stainless steel investment cast parts. Birchwood Technologies, Gesswein, Astro Chemicals, and Erie Plating are some of the top suppliers of black oxide equipment and services tailored for stainless castings. With the right process controls and expertise, they can deliver durable, uniform black oxide coatings that meet industrial specifications.

Black oxide finishing requires a thorough understanding of the process chemistry and variables that affect results on stainless castings. By outsourcing to a specialized blackening service provider, manufacturers can avoid the challenges of installing in-house equipment while achieving excellent quality. Whether purchasing turnkey equipment or utilizing a finishing service, choosing a provider with proven expertise in blackening stainless steel investment cast parts is key.