What are Black Stainless Steel Screws ?

Black stainless steel screws are a surface treatment of stainless steel 304 and 316 screws, after treatment, the formation of a black film on the surface of the bolts, can enhance the stainless steel fastener’s rust resistance.

There are different methods of black stainless steel bolts, including chemical blackening, electrolytic oxidation blackening, and chemical heat treatment blackening.

black stainless steel screws

Black Stainless Steel Screws Factory

Black Stainless Steel Screws Machine Thread

Black Stainless Steel Screws Machine Thread are made of stainless steel 304 or 316, with grade A2-70 or A4-80, the screws with machine thread, used for pre-threaded holes or fix with black stainless steel nuts. the screw end is flat, the ends can be chamfered if required, and it is friendly for automatic installation.

black pan head socket stainless steel screws
black pan head phillips screws

Cap Head Black Stainless Steel Screws

The Cap Head Black Stainless Steel Screws are DIN912 or ISO4762 standard screws, and the screw head with serration or without serration are available. all sizes with A2-70 or A4-80 in stock for fast shipment. the screws with full thread or partial thread are available from us. the Allen cap black screw without knurling is used well for solar mounting systems.

black oxide stainless steel screws
black stainless steel machine screws

Black Stainless Steel Screws Wood Thread

Wood thread Black Stainless Steel Screws are black self-tapping stainless steel screws with wooden thread, kind of head type, like pan head or countersunk head, with any type of drive, are produced by Ding Fasteners. For easier and faster tapping and clip removal, we can also groove the end of the black self-tapping screws.

black stainless steel wood screws
black stainless self tapping screws

Black Head Stainless Steel Screws

304 316 Black Head Stainless Steel Screws are the screws with the black head only. this blackening process is baked enamel at the screw head. of course, we can produce the stainless steel screw heads in any color.

Baking paint using excellent epoxy primer, polyester top coat, and high-temperature baking, and many years of mature technology, after spraying the product in the fastness, color thickness.

black head stainless steel screws
black head stainless steel self drilling screws

Types of Black Stainless Steel Nuts

For the assembly of black 304 316 full thread screws, we also produce black stainless steel nuts, all in the same material and grade as the screws. 

We produce a wide range of fasteners with a blackened finish, not only screws but also nuts, washers and thread rods, if you need our support and service, please contact us and we will reply to, you within 24 hours.

black stainless fasteners
black stainless steel flange nuts
black stainless steel fasteners

Mill Test Report of Black Head Stainless Steel Screws

All of our stainless steel fasteners are supplied with factory test reports, which include, customer information, order information, product information, sampling standards and quantities.

Detailed records of the actual measurement data of each size of the product, the number of passes and the number of rejects. Tests on through and through gauges.

Mill Test Report also shows the chemical composition of each component, as well as the mechanical properties, including tensile strength, elongation, and hardness, as required by the standard.

Of course, the thickness of the coating after surface treatment and the duration of the salt spray test are also included.

Ding Fasteners accepts third-party testing requirements, our products have been tested by SGS and TUV, if you need our report, please contact us.

Various Blackening Methods For Black Head Stainless Steel Screws

black countersunk stainless steel screws
black stainless screws
black socket stainless steel screws

Chemical Blackening Process

Divided into two kinds of acid blackening and alkaline blackening, acid blackening film layer is uniform, thin and solid, good bonding force, but the film layer is porous, poor abrasion resistance, curing treatment is required.

Alkaline blacking, although good abrasion resistance, but the processing time is long.

Electrolytic Oxidation Method

A film layer is thick, and the color is black, but the film layer is slightly less abrasion-resistant, poor sunlight resistance, and easy to crack automatically.

Chemical Heat Treatment Method

Carried out in special equipment, the film layer is strong, good bonding force, beautiful colour, dense surface layer.

Our stainless steel black fasteners are chemically heat-treated, and our heat-treated blackening process is as follows.

  • Preparation of blackening liquid: 1:8 or 2:7
  • Heat the screw without oil rust to 180-500℃, then put screws into the liquid to blacken instantly ( 10-20seconds)
  • Dry the water with hot air (180℃ for 5minutes) after the screw is tanken out.
  • Spray rust preventive oil ( KCH-207 environmentally compatible), then for packing.

  • The tempeature of the liquid is controlled within the range 45-55℃.

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