Surface Finishes
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Different European norms define product surfaces depending their grades. The European norm EN 10088 defines various standard mill surface finishes having as main distinction the production process, either hot or cold produced.

All stainless steel profiles provided by Peak Kong Special Steel can be classified according to these tables. Depending on the manufacturing technology, we offer the following standard finishes for our profiles:

Stainless Steel Mill Finish
1D finish – Hot Rolled
The 1D finish is our standard for hot rolled sections in stainless steel. These sections are heat-treated and a final acid pickling process removes the rolling scale. This finish is not free of surface imperfections. Imperfections are defined by the EN 10163-3. Hot rolled products are suitable for applications, where no particular aesthetic conditions are requested on the surfaces, but mainly are functional. With additional processing such as polishing or cold drawing a better finer surface can be reached.
Hot Rolled
1D finish – Laser Welded
The 1D finish is the common finish for our laser-welded sections in stainless steel. These sections are produced from strips, which are cut from hot rolled, annealed and pickled plate. The finished product is sand blasted, passivated and free from scale. Processes of welding and final straightening affect the surface. This finish is not free of surface imperfections. Imperfections are defined by the EN 10163-3-D1. Laser fused profiles from YamKong have an extraordinary clean and homogeneous surface and are already in with the standard mill finish suitable for a wide range of applications.
These products are suitable to be used in their present condition or to be further processed. With additional processing such as polishing or cold drawing a finer surface can be reached.
Laser
2H finish – Cold Drawn and Cold Rolled
The 2H finish is our standard for cold rolled or cold drawn stainless steel section, which is a smooth, matt or bright surface. Cold formed products – depending on their deformation level – have substantially increased tensile strengths. This strain hardening can be lowered by a following heat treatment without affecting the surface, for example by annealing. Admissible Imperfections are defined by the EN 10277-1.
These products are suitable to be used in their present condition or to be further processed. Cold worked profiles from YamKong have process-related a very smooth surface and are already with the standard mill finish suitable for a wide range of aesthetic applications. With additional processing such as grinding or polishing, a finer surface can be reached.
Cold Drawn and Cold Rolled
Steel Mill Finish
AR finish – Hot Rolled
The AR finish (meaning as rolled) is our standard for hot rolled sections in in carbon steel, which is defined by EN 10025. The hot rolling and the final straightening process affect the surface. Admissible imperfections are defined by the EN 10163-3. Hot rolled profiles from YamKong have in their crude condition an above-average good surface and are already with the standard mill finish suitable for a wide range of aesthetic applications. With additional processing such as cold drawing a finer surface can be reached.
Hot Rolled
Sa 3 finish – Laser Welded
Laser fused profiles from YamKong Special Steel are manufactured with sheet metal strips, which are taken from hot rolled, annealed and pickled respectively blasted sheets. Processes of welding and final straightening affect the surface. This finish is not free of surface imperfections. Imperfections are defined by the EN 10163-3-D1.
Laser fused profiles from YamKong Special Steel are blasted at the end of the production chain and therefore have an extraordinary clean and homogeneous surface. Our profiles in their standard mill finish can be classified under surface class Sa 3 of the EN (ISO) 8501-1. The blasted surface has a grey-white metallic appearance and is slightly roughened from the blasting shot, which allows a good adhesion of eventually applied coatings. The surface is free of dirt, oil, grease, visible scale, rust, corrosion products, oxides, paint or other contaminants. This surface condition is suitable for a wide range of applications. With additional processing such as polishing, a finer surface can be reached.
Laser
Surface Refinement

Often an additional refinement of the surface is requested for stainless steel products. These surface refinements can be classified according to EN 10088-2, in which the digit “1” stands for hot rolled and the digit “2” for cold rolled raw material:

Execution Description Grain Typical Ra-values
1G / 2G Ground 120 2.5-2.0 µ
1J / 2J Brushed 180 1.2-1.0 µ
1J / 2J Dull-polished 240 0.6 µ
1K / 2K Satin-polished 320 0.5 µ max.
1P / 2P Bright-polished 600 0.1 µ
1P / 2P Mirror-polished 800 0.05 µ

For technical applications the roughness (Ra value) is sufficient for the definition of the needed product surface. If it is an aesthetical application, the general appearance is crucial and therefore should be defined by using a sample. Please contact us, we are happy to consult you.

Laser