Blog | Huaxin Stainless

Stainless Steel Surface Treatment

Wed, 14 Jan 2026 13:37:03 +0800

Stainless steel is widely applied in construction decoration, kitchen and bathroom appliances, machinery manufacturing, medical devices, food processing and other industries due to its excellent corrosion resistance, mechanical properties and aesthetic appeal. Stainless steel surface treatment technology not only further enhances the appearance texture of stainless steel products but also strengthens their core performances like corrosion resistance and wear resistance, perfectly adapting to the usage demands of diverse scenarios. This article will elaborate on various stainless steel surface treatment methods, analyzing their process characteristics, application scopes and core advantages for industry professionals and buyers.

1. Vibratory Polishing

Vibratory polishing is a common stainless steel surface treatment method, mainly used for mass finishing of small to medium-sized stainless steel workpieces. It works by placing workpieces, abrasives (such as ceramic stones, plastic pellets), and polishing compounds into a vibratory machine. The machine generates high-frequency vibrations to drive mutual friction and impact between workpieces and abrasives, thereby removing burrs, sharp edges and surface defects, and achieving a smooth, matte or semi-bright surface finish.

This stainless steel surface treatment process is highly efficient for batch processing, especially suitable for workpieces with complex shapes, holes or gaps that are hard to polish by hand or mechanical polishing. It ensures uniform polishing effect, maintains the dimensional accuracy of workpieces without deformation. Common applications include stainless steel fasteners, hardware accessories, jewelry components, tableware and small mechanical parts.

Its advantages are high production efficiency, low labor cost, uniform polishing effect and strong adaptability to complex workpieces. The disadvantages are that it is not suitable for large workpieces, the polishing precision is lower than electropolishing and fine mechanical polishing, and subsequent polishing steps may be required to achieve a mirror finish.

Vibratory Polishing

2. Mechanical Polishing

Mechanical polishing is one of the most basic and widely used methods in stainless steel surface treatment. Its core principle is to remove defects such as oxide layers, scratches and burrs on the stainless steel surface through mechanical cutting or grinding with tools such as grinding wheels, cloth wheels and polishing wax, so as to achieve a flat and bright surface.

According to polishing precision, mechanical polishing can be divided into three stages: rough polishing, medium polishing and fine polishing. Rough polishing mainly removes obvious surface defects to lay the foundation for subsequent polishing; medium polishing further refines surface texture and reduces roughness; fine polishing can make the stainless steel surface show a mirror finish with a reflectivity of more than 80%. This process is suitable for various stainless steel products, such as stainless steel kitchenware, tableware, decorative panels and hardware accessories.

Its advantages lie in mature technology, simple operation and intuitive polishing effect, which can maximize the metallic texture of stainless steel. The disadvantages are that it is difficult to polish workpieces with complex shapes, uneven polishing is easy to occur at edges and corners, and there are micro-scratches (invisible to the naked eye) on the surface after polishing, which may still cause local rust when exposed to a humid environment for a long time.

Mechanical Polishing

3. Pickling and Passivation

Pickling and passivation is a core stainless steel surface treatment process designed to improve corrosion resistance. It is mainly used to remove oxide scales, weld spots, iron contamination and other substances generated on the stainless steel surface during processing. At the same time, a dense passive film (mainly composed of Cr₂O₃) is formed on the surface, which blocks the contact between corrosive media and the substrate and greatly enhances the corrosion resistance.

The process flow usually includes degreasing, pickling, water washing, passivation, secondary water washing, drying and other steps. Degreasing can remove surface oil stains to create conditions for pickling; pickling mostly uses a mixed solution of nitric acid and hydrofluoric acid, which can quickly dissolve oxide scales and impurities; passivation generates a stable passive film through chemical reaction to extend the service life of stainless steel. This process is widely used in chemical equipment, pressure vessels, pipelines, stainless steel components and other scenarios requiring high-strength corrosion resistance.

The advantages are significant improvement in corrosion resistance, the passive film does not affect the matrix properties of stainless steel after formation, and the process has strong adaptability and can handle workpieces with complex shapes. The disadvantages are that the surface is matte grayish white after treatment, with general aesthetics. If the pickling concentration or time is not properly controlled, it may cause over-corrosion of the surface and affect the workpiece precision.

Pickling and Passivation

4. Electropolishing

Electropolishing, also known as electrochemical polishing, is a precision stainless steel surface treatment technology based on the electrolysis principle, belonging to the anodic dissolution process. The stainless steel workpiece is used as the anode and placed in an electrolyte composed of phosphoric acid, sulfuric acid, etc. By applying specific current and voltage, the metal atoms on the workpiece surface are selectively dissolved to achieve a flat and bright surface. At the same time, it can optimize the surface structure and improve corrosion resistance.

Compared with mechanical polishing, electropolishing can handle workpieces with complex shapes and small gaps, and there is no residual mechanical stress on the surface after polishing. The glossiness is more uniform and durable, reaching a mirror-level effect, and some high-end products can even achieve "mirror without trace". This process is often used in medical devices, food processing equipment, precision instrument accessories, high-end decorative stainless steel and other products with high requirements for surface precision and corrosion resistance.

The advantages are high polishing efficiency, excellent surface quality and better corrosion resistance than mechanical polishing. The disadvantages are that the electrolyte is corrosive, requiring proper environmental protection treatment, high equipment investment cost, and strict control requirements for process parameters (current, voltage, temperature).

Electropolishing

5. Sandblasting

Sandblasting is a stainless steel surface treatment process that sprays abrasives (such as quartz sand, alumina sand and emery) onto the stainless steel surface at high speed via compressed air. With the impact and cutting effect of abrasives, a uniform rough surface is formed on the surface, showing a matte and frosted texture. According to different types and particle sizes of abrasives, various surface effects with different roughness can be created, from delicate matte to rough granular feeling.

This process can not only improve the appearance layering of stainless steel, but also enhance surface adhesion, providing a good base for subsequent painting, coating and other treatments. Application scenarios include architectural decorative panels, elevator panels, stainless steel doors and windows, hardware accessories, etc., especially suitable for products pursuing a low-key and wear-resistant texture.

The advantages are flexible process, unique surface effect and strong wear resistance. The disadvantages are that the rough surface is easy to accumulate dust and dirt, the cleaning difficulty is slightly higher than that of smooth surface, and dust is generated during the treatment process, requiring environmental protection dust removal equipment.

Sandblasting

6. Coloring Treatment

Stainless steel coloring treatment is a specialized stainless steel surface treatment that forms a colored oxide film or composite film on the surface through chemical, electrochemical and other methods. It retains the original properties of stainless steel while enriching its appearance colors to meet personalized design needs. Common coloring processes include chemical coloring, electrochemical coloring, vacuum coating coloring (PVD) and more.

Chemical coloring involves putting stainless steel into a specific chemical solution to form an oxide film through oxidation reaction. The color can be adjusted by controlling reaction time and temperature, such as gold, brown, blue, black, etc.; electrochemical coloring generates an oxide film with the help of electrolysis, with more uniform color and stronger stability; vacuum coating coloring (such as PVD coating) deposits metal ions such as titanium and zirconium on the stainless steel surface in a vacuum environment to form a wear-resistant and corrosion-resistant color film. The colors include rose gold, champagne gold, gun gray, etc., with high-end texture.

Coloring treatment is widely used in high-end architectural decoration, jewelry, hardware accessories, home appliance casings and other fields. The advantages are rich colors, good appearance texture, and strong wear resistance and corrosion resistance of the film layer. The disadvantages are high process cost, some coloring methods have requirements on the use environment, and fading and film peeling may occur after long-term exposure to sunlight or corrosive substances.

Coloring Treatment

7. Coating Treatment

Coating treatment is a protective stainless steel surface treatment that involves pasting a polymer film (such as PVC film, PE film) on the stainless steel surface to prevent scratches and pollution. Some coatings also feature specific patterns, textures or colors, offering both protective and decorative functions. It can be divided into single-sided and double-sided coating based on usage needs, with film thickness ranging from several microns to tens of microns.

This process is mainly used in the production, transportation and installation of stainless steel plates, coils, doors and windows, kitchenware and other products. It can effectively avoid surface damage during processing and handling. After installation, the film can be torn off to expose the original surface of stainless steel. Some functional coatings (such as antibacterial film, anti-fingerprint film) can also endow stainless steel with additional properties and expand application scenarios.

The advantages are low cost, good protection effect, convenient operation, and can be used with other surface treatment methods. The disadvantages are that the film has a service life, is easy to age and fall off when exposed to high temperature and ultraviolet environment for a long time, and inferior coating may leave adhesive marks, affecting the appearance.

Coating Treatment

8. Other Special Surface Treatments

In addition to the aforementioned common stainless steel surface treatment methods, there are targeted special processes to meet specific scenario requirements. For instance, anti-fingerprint treatment (a functional surface treatment) applies an oil-repellent, water-repellent nano-coating to reduce fingerprint residue, widely used in home appliance panels, mobile phone accessories and bathroom products. Antibacterial treatment adds components like silver ions to inhibit bacterial growth, suitable for medical devices and food processing equipment. Nitriding treatment enhances surface hardness and wear resistance, applied to mechanical parts and cutting tools.

Conclusion

The selection of stainless steel surface treatment technology should be comprehensively considered based on the product’s application scenario, performance requirements, appearance design and cost budget. Each stainless steel surface treatment method has its unique advantages and disadvantages; reasonable combination (such as pickling and passivation + brushing, electropolishing + anti-fingerprint treatment) can maximize stainless steel’s performance advantages and increase product added value. With technological advancement, new stainless steel surface treatment processes (like environmentally friendly electrolyte polishing, multi-functional composite film coloring) are gradually popularized, expanding the application scope of stainless steel products.

Check the BL of Stainless Steel Link Chain

Thu, 19 Dec 2024 10:15:10 +0800

A tensile testing machine, also known as a universal testing machine (UTM) in some cases when it can perform multiple types of tests, is a crucial piece of equipment used in materials testing.

We have a 60 ton universal testing machine that can test the mechanical properties of most of our products in our current product range.

The following video shows how we conduct the breaking load test on the 8mm short-link stainless steel chains.

Bimini Tops and Stainless Steel Hardware

Mon, 01 Jan 2024 16:01:20 +0800

Introduction

Bimini tops are essential accessories for boats, offering protection from the sun and harsh weather conditions. These tops, coupled with durable stainless steel hardware, form a robust and long-lasting solution for boaters seeking comfort and safety on the water.

What is a Bimini Top?

A Bimini top is a canvas or cloth covering supported by a frame that provides shade and shelter on a boat. Typically adjustable, these tops are designed to cover a portion of the cockpit area, enhancing the boating experience by offering a reprieve from sun and rain.

The Importance of Stainless Steel Hardware

The choice of hardware for Bimini tops is crucial. Stainless steel hardware stands out due to its:

1. Corrosion Resistance: Stainless steel resists rust and corrosion, making it ideal for marine environments where saltwater and humidity are prevalent.

2.Strength and Durability: It withstands harsh marine conditions, including strong winds and saltwater exposure, ensuring the Bimini top remains securely in place.

3.Aesthetic Appeal: Stainless steel offers a sleek and modern look that enhances the boat's appearance.

Key Stainless Steel Components in Bimini Tops

1.Frames: The backbone of Bimini tops, these frames are often made of high-grade stainless steel for maximum strength and durability.

2.Mounting Hardware: This includes screws, bolts, and deck hinges, all of which are vital for securing the top to the boat. Stainless steel variants ensure longevity and reliability.

3.Fittings and Joints: Essential for the structural integrity of Bimini tops, stainless steel fittings like eye ends, jaw slides, and deck hinges provide flexibility and strength.

Maintenance and Care

While stainless steel is low maintenance, regular cleaning with fresh water and periodic checks for tightness and alignment can extend the life of the hardware and the Bimini top.

Conclusion

Bimini tops equipped with stainless steel hardware are an investment in both the functionality and aesthetics of a boat. They not only provide necessary protection from the elements but also enhance the overall boating experience. The durability and strength of stainless steel hardware ensure that these tops can withstand the rigors of marine environments, making them a wise choice for any boater.

Electric Discharge Drilling

Sun, 24 Dec 2023 15:37:34 +0800

Electric discharge drilling, also known as EDM drilling, is an advanced machining technology commonly used for processing hard materials or parts with complex shapes. This article will detail the advantages and disadvantages of electric discharge drilling, especially when working with stainless steel materials.

Advantages

High Precision: Electric discharge drilling is capable of processing very fine holes, making it suitable for applications that require high precision.
Strong Material Adaptability: This technique can easily process hard materials, such as stainless steel, without being limited by the hardness of the material.
Complex Shape Processing: It allows for the machining of various complex shapes, including tapered holes, blind holes, etc.
Good Surface Quality: The heat-affected zone produced during the process is small, enabling a better surface finish.
No Mechanical Stress: As a non-contact machining process, it doesn’t subject the material to mechanical stress, reducing the likelihood of deformation.

Disadvantages

Slow Processing Speed: Compared to traditional mechanical drilling, electric discharge drilling has a slower processing speed.
Higher Cost: Both the equipment cost and operating cost are relatively high, especially in large-scale production.
High Energy Consumption: The process consumes a significant amount of electricity.
Maintenance Requirements: Regular maintenance and replacement of consumables, like electrodes, are needed.
Heat Affected Zone: Although small, it still exists and can affect the microstructure of the material.

Special Considerations for Stainless Steel

For hard materials like stainless steel, electric discharge drilling is an ideal method. Stainless steel poses challenges to traditional mechanical machining due to its high hardness and toughness, which can lead to tool wear and low machining efficiency. Electric discharge drilling allows for high-precision machining of stainless steel without compromising the integrity of the material structure.

Conclusion

Electric discharge drilling is a powerful machining technique, particularly suitable for the precision machining of hard materials like stainless steel. While its processing speed and cost may be limiting factors, its advantages in precision, material adaptability, and ability to process complex shapes make it the preferred technology for many high-precision applications.

13th Fastener Exhibition Shanghai

Wed, 07 Jun 2023 09:25:57 +0800

On June 5-7, 2023, the 13th Shanghai Fastener Exhibition (FES 2023) was held at the National Convention and Exhibition Center (Shanghai). The exhibition covers an area of 60000 square meters, focusing on products, technological innovation, and solutions throughout the fastener industry chain.

We exhibited stainless steel fasteners and rigging products and received numerous inquiries from visitors.

Magnetism of Stainless Steel Material

Wed, 10 Jan 2018 08:49:15 +0800

Someone always judge the authenticity of stainless steel by magnetism. They thought if the material can be sucked by the magnetic-iron, it colud not be stainless steel, at least, it colud not be good stainless steel material. Actually, it's nothing about magnetism, the only way to judge them is to analysis the chemical elements.

We know that 304 stainless steel belongs to the austenite type, but the austenite is no magnetic or weak magnetic, so people will think that the good stainless steel is no magnetic. However, we ignored that the smelting process or some other processing can caused magnetism while its chemical composition fluctuation , it can not be considered to be counterfeit or substandard products. In addition, after cold working, the organizational structure of or processing will be transformed to martensite, the greater the degree of cold deformation, the more martensite transformed and the magnetism is bigger. On the contrary, the 200 series of stainless steel, which has lower quality, is very likely not to be magnetic.

In particular, it is suggested that the magnetism of the 304 stainless steel caused by these reasons is not the same level as that of the other materials, that is to say, the magnetism of the 304 steel always shows the weak magnetism. This tells us that if the stainless steel strip is weakly magnetic or completely magnetic, it may be 304 or 316 material. If the magnetism is the same as carbon steel, it is probably not 304 material.

If we need to identify the material clearly, we can further test it by stainless steel calibration medicine, chemical experiment analysis, spectrum detection and analysis. Among them, chemical experiment analysis and spectral detection analysis can identify the content of each element accurately, and it is the most effective method to identify the material.

Some Questions about Stainless Steel Electropolishing

Thu, 30 Nov 2017 20:09:32 +0800

What's stainless steel electropolishing?

Stainless steel electropolishing is used to polish, passivate stainless steel part. Stainless steel workpiece is connected to the positive terminal of a DC power. Both the workpiece and the negative terminal are immersed into the temperature-controlled electrolyte together. A current passes from the anode then the surface of workpiece is dissolved, that could improve the the surface, make workpiece shiny and smooth.

Comparison between passivation and electropolishing

a, Electropolishing can remove all surface contaminants but passivation can't

b, Passivation can't be performed on all grades of stainless steel neither

c, Electropolishing is preferred to passivation

d, Someone suggest it's necessary to passivate after electropolishing, because it could improve corrosion resistance.

Note on stainless steel electropolishing:

a, The space between electrolyte level and the top of tank can't be≤ 15cm, because there will be foam in initial use of electrolyte.

b, The moisture must be removed as much as possible before being immersed into electrolyte. Because too much moisture could cause serious pitting even lead to workpiece scrapped

c, During the process of stainless steel electropolishing, the iron and chromium contained in the workpiece continuously transform into metal ions dissolved into electrolyte without being deposited on the cathode surface. As the polish process, the concentration of metal irons increase gradually and when it reaches a certain value, the metal ions precipitated out of the electrolyte in the form of phosphates and sulfates, settling down at the bottom of the tank. So the electrolyte must be filtered regularly to remove the sludge.

Stainless Steel Eye Bolts

Fri, 17 Nov 2017 21:49:56 +0800

Eye bolts are commonly used as a lifting tool or securement point and they are widely used in all kinds of industrials. We could also use them to connect other rigging tools.

There are four basic types of eye bolts, regular eye bolts, shoulder eye bolts, screw eye bolts and machinery eye bolts. All four of these basic types that Huaxin Stainless offers are made of stainless steel to ensure greater rust resistance.

Regular and shoulder eye bolts are essentially the exact same part with the only obvious exception being the shoulder. The shoulder feature provides more stability to the base of the eye and therefore, makes it the recommended choice for angular loading. Regular eye bolts are not recommended for angular loading. Both regular and shoulder eye bolts have UNC type or metric threads.

Screw eye bolts are designed for screwing into wood or plastic. And because of this, do not have a working load limit assigned to them because it is not possible to determine the various densities and conditions of the wood the eye bolts are screwed into.

Machinery eye bolts are designed with a shoulder and are designed for angular loading. The difference between machinery eye bolts and regular and shoulder type eye bolts is that the shank and threads of the machinery eye bolt do not protrude through the base metal. Therefore, all of the holding strength of the machinery eye bolt is on the threads.

How To Install Frameless Glass Pool Fencing

Tue, 07 Nov 2017 14:01:17 +0800

1. Check the levels for your proposed fence lines, then mark out the glass panel sizes dividing them for the where spigots are going to be located. The spigot location on the fence line is approx. 25% of glass width. If the panel is 1200mm, the spigot location would be 300mm from the panel edge.

2. Using the supplied stainless steel plate and mark out the holes to be drilled. It's better to put some tap on the drill bit, so you know you get the depth you need.

3. Obviously you must clean the drilled holes by a vacuum cleaner, hold over on the holes, the dust could be sucked up then inject chemical anchoring system into the holes.

4. Place the spigot on top of the stainless steel plate and slot the bolt into the hole and tighten it to create maximum stability and next put cover ring over spigot.

5. Slowly place the glass into the center of the spigots, tight top grub screw on spigot with allen key.

6. Attaching the latch to gate when glass is set.

Silica Sol In Investment Precision Casting Process

Mon, 06 Nov 2017 22:16:50 +0800

Silica sol process, commonly known as investment precision casting, as a kind of casting process with less cutting or no cutting that was developed on the basis of ancient lost wax casting. As an excellent technology in the casting industry, it has been extensively applied.

China, as an ancient civilization, applied this technology earlier. The ancient Chinese working people created this kind of lost wax casting technology several centuries BC, and they used it for casting products such as tripod and household utensils with a variety of fine decorative pattern and text, such as the Tomb off Marquis Yi of Zeng during the Spring and Autumn Period.

Modern investment casting methods was practically applied in the industry production in the 1940s when the development of aviation jet engine required to produce complicated shapes, such as blade, impeller and nozzle, size precision and smooth heat resistant alloy parts. It is difficult to process heat resistant alloy materials, and the parts have complex shape, so that it can’t or difficult to be made through other methods. Therefore, it is necessary to find a new precision forming technology. By referring to ancient stream lost wax casting, and through the improvement of materials and technology, modern investment casting method has achieved important development on the basis of ancient technology. The development of aviation industry promotes the application of investment casting; the continuous improvement and perfection of investment casting also creates favorable conditions for the further performance improvement of aviation industry.

Simply speaking, investment casting process steps are as follows: Make into melt-able model (referred to as “investment pattern or model”) with fusible materials (such as wax material or plastic), apply several layers of tailor-made refractory coating; wait it to form a whole shell through drying and hardening, melt the model with steam or hot water from the in model shell, and then put model shell s in the sand box, fill in dry sand moulding all round, place the casting model into the furnace through the high-temperature roasting (for high strength shell, directly conduct roasting demoulding shell without modelling), pour molten metal after cast type or shell is roast.

Investment castings have high dimensional accuracy and surface finish, so they can reduce machining work, and it is ok to leave a little machining allowance on the parts with a little higher requirements and even some casting parts can leave only grinding, polishing allowance, and be directly used without needing machining. Therefore, investment casting method can considerably save machine tool equipment and processing time, and greatly save metal materials.

In addition, investment casting method can be used to cast complicated casting of all kinds of alloy, especially high temperature alloy castings. For example, it is almost impossible to form streamlined profile and cooling inner chamber of jet engine blades by machining work art. Investment casting process can not only achieve batch production, and ensure the consistency of castings, but also avoid the stress concentration of residual knife lines after machining.