Introduction to the Oxide Black Finishing of Precision Mechanical Components
Knowledge

Introduction to the Oxide Black Finishing of Precision Mechanical Components

In most cases, blackening treatment on steel, also known as black oxidation, can enhance corrosion resistance to a certain extent. However, the protective effect remains somewhat limited. To significantly improve both corrosion resistance and lubrication of the blackened layer, additional measures like oil immersion or subsequent rust prevention treatment are still necessary.
Published: Nov 03, 2023
Introduction to the Oxide Black Finishing of Precision Mechanical Components

To enhance the rust resistance of steel components, a process is employed to oxidize the steel's surface, creating a dense and smooth layer of iron oxide using potent oxidizing agents. This thin layer of ferro-ferric oxide effectively shields the interior of the steel from oxidation. The iron oxide formed at high temperatures, around 550°C, has a sky-blue hue and is known as "bluish treatment," which is commonly used in weapon manufacturing. In industrial production, the bluish treatment is also a popular choice.

The ability to generate this dense and smooth iron trioxide layer on steel surfaces depends on the selection of a strong oxidizing agent. This potent oxidant typically comprises sodium hydroxide, sodium nitrite, and trisodium phosphate. When in a molten state, they are applied to steel components for bluish treatment, while their aqueous solutions are used for blackening treatment.

Precision-machined parts crafted from iron-based materials, such as stainless steel alloys, can specify black oxide as a surface treatment to provide additional protection.

What is Black Oxide?

Black oxide, also known as oxide black, is a conversion coating formed through a chemical reaction when a part is immersed in an alkaline salt solution, usually at an elevated temperature. This reaction between the stainless-steel alloy and the solution generates a layer of magnetite on the part's surface. Magnetite acts as a protective barrier, preventing moisture from corroding the alloy surface. Since magnetite is black, the process is termed "black oxide."

The solution used in this process may vary slightly depending on the metal being treated. The treatment can be applied using cold, room temperature, or hot processing methods, and it may require pre-treatment of components based on their specific requirements.

One of the advantages of black oxide is that it forms an exceedingly thin layer of magnetite, serving as a moisture barrier. The typical thickness ranges from 5 to 10 millionths of an inch (.000005 inches to .000010 inches), ensuring that the process does not affect the part's dimensional stability. Furthermore, black oxide treatment does not remove or deposit any metal from the part's surface, and unlike painted or electroplated treatments, it does not chip or flake.

Black oxide can also undergo post-treatment processes, such as oil, wax, or varnish, depending on the application and the desired appearance of the final part, ranging from a matte to a glossy finish. Post-treatment can also improve lubrication, making parts run smoother and enhancing their connection with matching components. The oil adds further corrosion protection. If black oxide is not specified for any post-treatment, the process is typically finished with oil.

The Applications of Black Oxide Can Be Specified

Components requiring compliance with MIL-DTL-13924D specifications for military purposes.

Surgical instruments in environments with reduced light to alleviate eye strain.

Gears, fasteners, and hardware in applications necessitating corrosion resistance.

Black hardware for construction and furniture assembly, adding an aesthetic touch to the final product.

Crucial factors to consider when specifying black oxide treatment include:

Duration of protection.

Indoor or outdoor usage.

Desired appearance (matte or glossy).

Environmental conditions (humidity, steam, temperature).

Intended use of the product.

Testing Options:

Various testing options are available for black oxide treatment, and they can be specified on the part drawing, but they may add to the time and cost of the process:

Stain Test:

This test checks for the presence of black powdery residues on parts when rubbed by hand after the treatment.

Relative Humidity Test: This procedure employs the ASTMD 2247 standard specification to evaluate corrosion resistance concerning water resistance of coatings at 100% relative humidity.

Published by Nov 03, 2023 Source: pioneerserviceinc, Source: itsfun

Further reading

You might also be interested in ...

Headline
Knowledge
Precision in Rotation: Indexing Plates in Metal Machining
Rotary Indexing Plates are precision components of milling machines that facilitate the precise angular positioning of workpieces and cutting tools. They are used in both metal machining and woodworking, and while they share a fundamental purpose, there are notable differences in their design, capabilities, and applications due to the distinct characteristics of the materials and processes involved.
Headline
Knowledge
Sheet Metal Fabrication Machines: An Overview
Sheet metal machines are widely used in various manufacturing industries for shaping, cutting, and forming sheet metal into different components. Some of the industries that extensively utilize sheet metal machines include light industries such as electrical and medical equipment, all the way up to heavy industries such as automotive, rail, oil and gas, as well as wind power generation.
Headline
Knowledge
The Significance of Planing Machines in the Machining Tool Industry
Metal and wood planing machines are essential tools in the machining industry. Wood planers use a rotating cutterhead equipped with sharp blades to smooth and size workpieces, ensuring uniformity in woodworking projects. Metal planers use a cutting tool mounted on a reciprocating tool head to remove excess material from metal surfaces, achieving precise dimensions in components. Both types of planning machines enhance efficiency, precision, and the overall quality of finished products. Understanding the key features of the various types of planing machines will help you choose the right machine best suited for your machining needs.
Headline
Knowledge
Stamp Press Technology and Manufacturing in Taiwan
Nestled in the heart of East Asia, Taiwan has emerged as a powerhouse in the global stamp press industry, with a robust manufacturing ecosystem, and cutting-edge technology. With a rich manufacturing tradition and a focus on precision engineering, Taiwanese companies meet the demands of diverse sectors, ranging from electronics and automotive to medical devices and aerospace, supplying high-quality stamp press solutions to a diverse range of markets worldwide.
Headline
Knowledge
Introduction to Stamp Press Technology
Stamp press technology, also known as stamping or pressing, is a manufacturing process that utilizes a press to shape or cut materials into desired forms. This process involves the use of a die and a punch to form or cut the material, creating intricate shapes with high precision. Widely employed for mass production due to its speed, accuracy, and repeatability, this process is a crucial part of modern manufacturing.
Headline
Knowledge
Mechanical Reducers in Industrial Manufacturing
Speed reducers are powerful mechanical devices generally used in machining tools to multiply the force or torque generated by an input power source, thereby increasing the usable force, enhancing the performance and precision of the machining tool. They are also used in material handling systems such as conveyor belts and lifting mechanisms to control the speed of material transfer and manage heavy loads efficiently. By multiplying the available output force, they enable the use of a reduced input power source, resulting in cost savings for machine tool investments. When choosing the appropriate speed reducer, the torque, speed, and horsepower of the input, as well as the mounting configuration, efficiency, and required lifetime all need to be considered. The quality of the machine chosen will also be reflected in the amount of backlash, transmission error, torsional rigidity, and inertia experienced during machining.
Headline
Knowledge
Introduction to Stamp Press Technology
Stamp press technology, also known as stamping or pressing, is a manufacturing process that utilizes a press to shape or cut materials into desired forms. This process involves the use of a die and a punch to form or cut the material, creating intricate shapes with high precision. Widely employed for mass production due to its speed, accuracy, and repeatability, this process is a crucial part of modern manufacturing.
Headline
Knowledge
Innovations in Sawing Technology
The traditional image of saws as just cutting tools is being reshaped by cutting-edge advancements that integrate automation and robotics in sawing technologies, paving the way for greater precision and efficiency of sawing technology in manufacturing.
Headline
Knowledge
The Fundamentals of Drilling Machines
Drilling machines play a pivotal role in the manufacturing industry, using rotary motion to create precise holes in a variety of materials. Whether it's metal, wood, plastic, or composites, drilling machines are versatile and essential for producing components in countless applications.
Headline
Knowledge
Hybrid Milling in Manufacturing: Integrating Additive and Subtractive Processes
The integration of additive manufacturing (AM) and subtractive milling processes has emerged as a transformative manufacturing process known as hybrid milling. This technique combines the strengths of both 3D printing and traditional subtractive milling, opening up new possibilities and diverse applications for creating complex geometries with improved material efficiency.
Headline
Knowledge
Features and Mechanics of Industrial Saws
Industrial saws shape raw materials into precise components that form the backbone of countless products. Understanding the mechanics of sawing, examining the fundamental principles, cutting mechanisms, and essential aspects of safety and maintenance will ensure the most efficient and safe operation of industrial saws.
Headline
Knowledge
Understanding the Diversity of Industrial Saws
Industrial saws play a pivotal role in processing a wide range of materials with precision and efficiency. Taiwan is a major supplier of industrial saws to the automotive, aerospace, and construction, as well as the metal fabrication industries. This article aims to provide a comprehensive understanding of the diverse industry of industrial saws, exploring their types, structures, applications, and the crucial role they play in various industries.
Agree