Further Study of stainless steel surface processing

Some kinds of Surface State

 

1.2 Surface--Roughness

Although there are more factors affecting stainless steel surface, but its cold-rolling process is a decisive factor. Surface roughness reasonable rolling schedule (reduction passes allocation, tension, speed settings, etc.) and roll. 2B product surface roughness as shown in Figure figure1.

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Different rolling processes relationship with grinding grit roughness

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SUS304 Surface finish by a variety of processing

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Cold rolling has higher hardness than the hot rolling. Cold rolling surface has less grit roughness than hot rolling. No.2 has less grit roughness than No.1.

 

After cold rolling, annealed steel is to be pickled, cold-rolled products of iron scales is less firm than hot rolled scales. Therefore, cold rolled product will be applied with chemical descaling method.

 

 

Temper rolling after annealing and pickling is, the use of large diameter mirror-finished rolls were 0.2% to 2% reduction processing method. To increase the gloss, glossy surface than 2D when austenitic stainless steel, said NO.2B processing. Its surface showed whitish gloss is the most dense skin.

 

Temper rolling is the afterwards process after pickling. Large diameter mirror finished rolls are to be applied to reduce the surface roughness. No.2B is more polishing than No.2D, it has a dense and white surface.

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Examples of surface finish on SUS304

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Deep processing of stainless steel surfaces

For some special purpose, you must change the nature of the surface of stainless steel, stainless steel surface can further processing by different processes. These deep-processing industry is mainly composed of surface treatment to complete.

 

—Polishing and Grinding

 

Considering ornamental and functional aspects, there are many value added surface processing. Typical polishing has HL, No.4, mirror, vibration, shot blasting and polishing wheel processing method.

 

No.4 product coil surface roughness. It causes the polishing abrasive under pressure with a rotary, stainless steel plate by its lower, with the HL processing of different, having a polishing stripe short characteristics. Polishing abrasives number is generally 180 to 240 #, mainly used in the interior wall of the timber and timber kitchen

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Typical surface finish stainless steel polished surfaces / μm

 

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Polishing grinding classification

 

HL processing:

One side of the belt against the steel surface, side stripes on the hair-like fine Indian steel slide.

General HL mostly conducted before processing base and Polishing (240 ~, etc.) processing.

Generally used 80 to 180 # abrasive to produce a different surface.

Because of its beautiful appearance and more for elevators and automatic lifts and so on.

 

No.4 processing:

 

It has shorter grit line that HL. The other process is similar.

 

 

Mirror finish: ----- 8K mirror panels

Quality mirror two types, one is only a mirror of raw materials processed through the grinding process; the other is to use the wheel to first remove small defects material surface, then polish mirror finish.

After processing, the surface appearance beautiful, smooth finish. So most of the use of the building entrance and interior decoration decoration.

 

 

Vibration processing:

In the non-woven fabric containing grit polishing head, rotating and moving alternately given polishing method of random motion.

Raw material: 2B and BA material, often used in the construction of exterior and interior doors and elevators.

 

Shot peening

Glass beads with compressed air while the steel sheet surface to high-speed impact, the method produces an uneven surface on the surface.

Impact energy greater peening process is commonly used No.1 surface, typically used peened sheet method is weak impact energy working method. --- Visual feeling: soft, interior and exterior building materials.

 

Buffing process

Raw materials: high-speed rotating 2D material, sisal and cotton is to be made to overlap and make cylindrical buff, buff the surface facing a supply side abrasive polishing method, the surface shiny, (54 "polishing machine )

 

Grinding base:

Grinding No.1 wood and slab type, as in addition to surface defects (scale, pits, etc.), typically a substrate to be polished.

Grinding is a base for people to call or re-grinding grinding, the technology a great influence on the final grinding plant quality and cost.

 

Embossed surface

 

Rolling surface hardening wood products and embossing material:

Hardening material requiring the use of steel hardness, embossing material is subjected to uneven pattern in the steel surface, for applications requiring finish and ornamental areas.

 

 

Embossed stainless steel plate board

When rolling is embossed with a pattern roll rolling work, the work roll is usually processed with etching liquid, the depth of the board due to uneven pattern differs, about 0 ~ 20μm.

 

 

Painting

 

Once the stainless steel surface coating will lose their luster and color, so that the same appearance and color plates, and therefore be able to see the development of a transparent coating stainless steel substrate. However, ornamental importance in the construction field, it has developed a variety of color coating.

Its advantages: ① luster due to the adjustment, the board is not obvious, such as depression. ;

② not only entertaining, but also the development of both heat resistance, water resistance, anti-bacterial resistance and lubricity functions such products, and look forward to expanding the use.

 

 

Colouring

 

This method uses camera parts and precision machinery and other small parts. The member is immersed in about 400 ℃ molten salt, so that the method and the method of forming an oxide film with a cured black film.

Temper color Stainless steel under 300 ~ 900 ℃ heated when the thickness of the oxide film with the heating temperature change, the interference color appeared showing various colors, gold has been used for a motorcycle the muffler .

INCO coloring. The method is a chemical method of making a transparent oxide film having a thickness of about 0.1 ~ 0.3μm, and the passivation film is 0.001μm. Controlling the thickness of the oxide film can show a variety of specific colors used in the bath, etc.

 

Electroplating

 

Stainless steel having a passivation film due to unfavorable electrical conductivity and solderability, plating often used for this method. These plating methods are electrical plating method, electroless plating, hot dipping, vapor phase plating method.

 

Because plating characteristics, the development direction:

 

(1) nickel-plated stainless steel

(2) Copper Stainless Steel

(3) gold plated stainless steel

 

Stainless steel surface treatment technology outlook

 

  1. Nitriding surface hardening treatment

2.Laser irradiation is performed on the surface of stainless steel and silicon infiltration (Si), so that the surface strength and improved corrosion resistance after the coloring.

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