The Knowledge Related To Scrap Steel Recyclin

1. Definition of scrap steel
Scrap steel that is eliminated or damaged in the process of production and life and used for recycling is a general term for ferrous metal waste, including scrap steel, scrap iron, metallurgical waste slag, oxidized waste, etc. Among them, scrap steel is a clean raw material with a high recovery rate and consumes the same heat. The output rate of adding pure scrap steel is 95% to 96%, while the output rate of adding iron ore is only 65% to 66%. 
Scrap steel comes in various shapes, which are affected by factors such as aging, effectiveness (rust caused by long-term accumulation), fatigue (element changes caused by the growth of processed finished products over time), etc. Compared with successfully produced steel, performance is reduced.

The iron and steel scraps (such as trimmed edges, cut ends, etc.) that have not become products during the production process of the steel plant, as well as the iron and steel materials in the equipment and components that are scrapped after use, are called scrap steel; those that are composed of pig iron are called scrap iron, collectively referred to as scrap steel.

2. Conceptual distinction of scrap steel
The carbon content of scrap iron is generally greater than 2.0%. The sulfur content (mass fraction) and phosphorus content (mass fraction) of high-quality scrap iron are not greater than 0.070% and 0.40% respectively.
The sulfur content (mass fraction) and phosphorus content (mass fraction) of ordinary scrap steel and alloy scrap iron are not greater than 0.12% and 1.00% respectively. The iron content of blast furnace additives should not be less than 65.0%.
The carbon content of scrap steel is generally less than 2.0%, and the sulfur content is no more than 0.050%. The residual elements in non-alloy scrap steel should meet the following requirements: the mass fraction of nickel shall not be greater than 0.30%, the mass fraction of chromium shall not be greater than 0.30%, and the mass fraction of copper shall not be greater than 0.30%. Except for manganese and silicon, the total content (mass fraction) of other residual elements shall not exceed 0.60%.

3. Recycling methods of scrap steel
Social recycling: mainly comes from scrap iron and steel of poor quality eliminated from people's lives, generally classified as medium scrap or below. 
Industrial recycling: It mainly comes from the trimmings eliminated in factory production and is of high quality. It is generally divided into heavy scrap, fine furnace charge, high-quality scrap, washed scrap, special quality, and pure scrap.
Imported recycling: Imports mainly come from the United States and Japan. The United States mainly provides HMS#1 scrap steel, crushed materials, and high-quality scrap steel. Japan mainly provides HS scrap, H1 scrap, H2 scrap, and H1:H2 (50:50) mixed scrap.
Comparison of domestic and foreign scrap steel standards:

Chinese market: heavy scrap=6mm, medium scrap=4mm;

American market: HMS1=6mm, HMS2=4mm;

European market: E1=6mm, E2=4mm;

Japanese market: heavy melting HS1=6mm, remelted HS2＝4mm

4. Processing methods of scrap steel
Scrap steel has the characteristics of different types, shapes, weights, and sizes. The scrap steel supply department needs to use processing methods to process different types and specifications of scrap steel into furnace materials that meet the requirements by steelmaking production requirements.
While processing, it is necessary to select profiles, steel plates, etc. that can be directly used, and after shearing and gas cutting, use them as direct production materials, thereby increasing the utilization value of scrap steel and making the best use of them. Factory scrap and social scrap will be sorted and processed by steel companies or dealers.

5. The difference between ordinary scrap steel and stainless steel scrap
In the process of producing stainless steel round steel and stainless steel flat steel, there will be some leftover materials. These leftover materials are also fully utilized by many companies. What is the difference between such scrap stainless steel and ordinary scrap steel?
Toughness and hardness: Ordinary scrap steel is soft and tough, easy to bend but not easy to break; chromium stainless steel scrap is hard and can be bent but not broken when hit; nickel-chromium stainless steel scrap is tough and can be bent but not broken when hit.
Oxidation resistance: Ordinary scrap steel is easy to oxidize and rust, turning yellow; chromium stainless steel scrap is not easy to rust; nickel-chromium stainless steel scrap is not easy to rust.
Color: Ordinary scrap steel is dark brown; chromium stainless steel scrap is white after pickling; it is brown-black without pickling; nickel-chromium stainless steel scrap is silver-white after pickling; it is brown-white without pickling (chromium manganese nitrogen steel is black, hard); cold-rolled without annealing is silvery white, reflective, and hard in nature.
Magnetism: Under normal circumstances, ordinary scrap steel can be attracted by magnets; chromium stainless scrap steel is magnetic and can be attracted by magnets; nickel-chromium stainless scrap steel is non-magnetic in the annealed state. After cold working, there will be a little magnetism, but high manganese steel and chromium-manganese steel with higher manganese content are not magnetic. 
Gloss: Ordinary scrap steel is shiny without oxidation; chromium stainless scrap steel is dull; nickel-chromium stainless scrap steel is shiny.
The difference between wiping with copper sulfate: ordinary scrap steel turns purple-red; chromium stainless steel scrap does not change color; nickel-chromium stainless steel scrap does not change color after scraping off the oxide layer and dripping a little water with copper sulfate.