304 Grade Unpickled Stainless Steel Coil

Production introduction The term "pickling" means that the material has been developed to remove high temperature oxides that appear on the surface after annealing or soldering. Removing these oxides helps restore the inherent corrosion resistance of stainless steel. The pickling...

Product Details

Production introduction

The term "pickling" means that the material has been developed to remove high temperature oxides that appear on the surface after annealing or soldering. Removing these oxides helps restore the inherent corrosion resistance of stainless steel. The pickling solution can be applied by dipping the stainless steel into the bath, spraying the surface or applying a small amount of pickling paste with a brush.

Without pickled, the stainless steel coil appears black and dark on the surface, which is what we call "black coil".

Chemical Composition of Stainless Steel Coil

304 Grade Unpickled Stainless Steel Coil


Thick: 1.8mm-4.0mm, or as your requirements

Width: 485-550mm, or as your requirements

Surface: No 1

Brand: Jinhai Metals

304 VS 316 Stainless Steel

1.304 stainless steel is austenitic stainless steel, and 316 series is martensitic stainless steel.

2. 304 stainless steel is not magnetic, 316 series is magnetic;

3. 316 is a kind of 300 series stainless steel, generally 304 will be better rust-resistant

Corrosion, some special places 316 is better than 304, for example, some need higher hardness but do not need good anti-rust ability and no corrosion resistance, then 316 will be much better;

4. 300 series of stainless steel can be improved by heat treatment, now the tableware is generally used in the 300 series for lower-end products, 304 for higher-end products, and some high-end 304 tableware will use 316L materials.

Physical Properties


1.Tensile strength σb (MPa) ≥ 520

2.Conditions yield strength σ0.2 (MPa) ≥ 205

3.Elongation δ5 (%) ≥ 40

4.Hardness: ≤ 200HV

The reasons of rust in 304 Stainless Steel


Chloride ions are widely present, such as salt/sweat/seawater/sea breeze/soil. Stainless steel in the presence of chloride ions, corrosion is very fast, even more than ordinary low carbon steel. Therefore, there is a requirement for the use environment of stainless steel, and it is necessary to wipe frequently to remove dust and keep it clean and dry. (This would give him a "useless".) There is an example in the United States: a company uses a oak container to hold a solution containing chloride ions that has been used for nearly a hundred years and is scheduled to be replaced in the 1990s. Because the oak material is not modern enough, the container leaks due to corrosion after 16 days of replacement with stainless steel.

-Solution treatment

The alloying elements are not dissolved in the matrix, resulting in a low content of the matrix microstructure and poor corrosion resistance.

-Intergranular corrosion

Such titanium and niobium-free materials have a tendency to intergranular corrosion. The addition of titanium and niobium, together with a stable treatment, can reduce intergranular corrosion. A high-alloy steel that resists corrosion in air or chemically corrosive media. Stainless steel has an aesthetically pleasing surface and good corrosion resistance. It does not require surface treatment such as plating to give full surface properties to stainless steel. One of the aspects of steel, commonly referred to as stainless steel. Representative properties include high-alloy steels such as 13 chrome steel and 18-8 chrome nickel steel. From the perspective of metallography, because stainless steel contains chromium and the surface forms a very thin chromium film, this film is isolated from the intrusion of oxygen in the steel to resist corrosion. In order to maintain the corrosion resistance inherent in stainless steel, steel must contain more than 12% chromium. Used in applications where soldering is required. The lower carbon content minimizes the precipitation of carbides in the heat affected zone near the weld, which may result in intergranular corrosion (weld erosion) in certain environments.

-Surface mark phenomenon

Surface trace phenomenon refers to the occurrence of wire-filled or dot-like pit mark defects on the surface of the product after deep processing of 304 stainless steel or processed products.

Cause: There are foreign objects on the surface and the surface of the mold, and there are scars on the surface of the pressure pad.

Countermeasure: Remove foreign matter, scars before processing, and remove orange peel by sufficient grinding.

-The orange peel phenomenon refers to a phenomenon in which a 304 stainless steel molded article has a shape like an orange peel in the case of grinding or other conditions.

Reason: The grinding is not sufficient. The larger the processing, the more serious the orange peel, the coarser the raw material grains, and the heat treatment softens.

Countermeasure: The deep-processed product is fully ground, and the suitable heat treatment conditions are selected to control the grain size of the raw material.


Standard exported packing by wooden pallets or iron steel as photos. Eye to Sky and Eye to Sides package are both acceptable.

304 Grade Unpickled Stainless Steel Coil


Products in stock can be prepare within 3 days after receiving deposit. Products as your order can be finished within 15 days under 500 tons.


30% T/T in advance, balance before shippment.

Contact us

Email: ray@zcssteel.com/claraho@zcssteel.com


Wedsite: www.zcssteel.com

Address: F5C02-10, 5th floor, 2nd building, Huiquan science park, No.88, Taoyuan east road, Shishan town, Nanhai, Foshan, GD, China

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