Today, high-quality development is a growing challenge that places a heavy burden on economic activists. Investing in major companies around the world is in need of risks and the hot rolled coil is one of the favorites because of the minor risks involved.
Without significant investment, here this matter identifies the steel production and casting parameters that have the greatest influence on the quality of hot-rolled products (sheet and coil) and the effect of reduction-based rolling on the final thickness of the product As an overheating.
check The results showed a correlation with the degree of grade reduction, but not with the age of the mold. Depending on the thickness of the rolled product, it can be said that the ratio decreases when the product is thicker (9 mm or more).
In the liquid state of the steel, it is important to reduce the content involved. This can be achieved by removing reactive oxygen species to intensify the diffusion process (after scrubbing in BOF), using an appropriate quality and quantity of deoxidizer (aluminum), and removing as much of the inclusions formed by gas scrubbing, but not very much. well. After oxygen blasting, the oxygen content in steel can reach 800-1000 ppm.
The difference between hot plate and cold plate indicates that their production process is different. From its beginnings to the present day, steel has been processed and used in a variety of ways, changing its shape, size and size. First, metals such as tin and lead were changed and used with two cast iron rollers.
Then there are the larger drums which are driven by horse power or water blades. Gradually, hot rolling entered this field, through experience and training, they found that 2 small rolls supported 2 large rolls for better rolling effect, and the rolling process became four rolls. In addition to the large and small coils known as cold rolling, factories and foundries build furnaces to melt and alter raw materials such as iron ingots, also known as hot rolling.
hot rolled plate
Hot-rolled sheets are produced at high temperatures (usually above 926°C, above the steel’s recrystallization temperature) through rolling rolls. Steel produced in this way is resistant to deformation during cold rolling and under tension and pressure, and can only be melted and deformed during hot rolling.
By raising the steel’s temperature above the crystallization temperature, it can be easily shaped and transformed into different sizes. An important point about the temperature required for hot rolling is that the temperature must be evenly distributed over the surface of the steel so that rolling and thickness changes can occur evenly.
Otherwise, parts that are heated more than others will roll earlier and will not get a uniform shape. In general, hot rolling is stopped when the temperature reaches 50-100°C above the crystallization temperature.
During hot rolling, as the roll moves over the molten metal, its length increases and its thickness decreases. If the metal is to have an extremely small thickness, the movement of the rollers does not push the metal forward but moves back and forth on the metal to reduce its thickness, but the cost of the tweed increases considerably.
Hot-rolled steel requires additional leveling, such as galvanizing or extending the leveling step to the end of the rolling line to increase the delamination (volume) of the volume-limited coil.
In general, hot rolling can leave defects on the surface, such as scales or pits, which require grinding and finishing to make the surface smooth and uniform. Therefore, the quality of hot-rolled steel is lower than that of cold-rolled steel. Hot-rolled sheets have a matte surface due to their surface contact with the atmosphere, which is why they are also called boards in the market.
List of hot-rolled sheets and coils
These specifications indicate the chemical quality and design quality of hot-rolled carbon steel according to the American Standard Sheets (ASTM A-1011 CS and DS). Commercial Steel (CS) comes in four different types: A, B, C, D. There are two different types of tensile steel (DS), A and B.
DS steel material is considered for parts that need to be bent, formed, drawn, drilled or welded. Commercial steels contain varying amounts of carbon up to 0.08%, 0.10% and 0.15%. Tensile steel contains aluminum alloys with the lowest carbon content (0.02% for type B).
Applications for these materials include agricultural equipment, automotive equipment, barrels, drums, and general sheet metal fabrication. This kind of steel can be bent in any direction at room temperature, its own flatness can reach up to 180 degrees, and the outer surface of the bending part has no cracks and tears.
For improved surface finish and improved machinability, this type of steel can be produced in through-plating, expandable leveling, or under acidic or oily conditions. For applications that require a more uniform and flat painted surface, there are surface sanding and special finishing processes.
What are the benefits of using a hot plate?
Hot plate production generally requires fewer steps than cold plates, and therefore costs less. Since the heating plate can be cooled down to room temperature, no cooling process is required.
Using a hot plate is ideal where dimensional tolerances are not so important, as the overall strength of the material and the uniformity of the surface is not a critical issue. In cases where the uniformity of the surface is important, sheet peeling can be removed by grinding. Different brushes or glossy finishes can also be used when the crust is removed from the surface of the sheet.
- Use of hot plate
- agricultural equipment
- Auto parts (for example, frames and rims)
- building materials
- Railway equipment (e.g. rails and carriage components) etc.
hot rolled coil in major companies
Plate is often the first steel used to produce other sections, both as plate and as a base product. Historically, a large part of the paper buying and selling market in Iran and around the world has been focused on black paper. Therefore, slate is considered to be the most important type of steel sheet, and the price of slate is an important factor for the price of other steel sheets or other profiles. Therefore, factories that produce black plates are very important.
factory that produces black sheets
Blackboard, also known as hot-rolled sheets, is a product of hot-rolled steel plate, billet and plate. The product is simple in the production process and low in price, and is the most widely used steel plate. Among the important uses of boards are the manufacture of various sections of steel, galvanized sheets, colored sheets and oiled sheets, as well as the construction of oil tanks and tanks, etc.
Chinese imports of 62% pure iron ore have fluctuated in a range of $100 and below over the past week, remaining steady at around $101 a barrel. tons CFR China by the end of the week. The commodity market is expected to remain relatively stable in the short term.
While Chinese ports face quarantine, high stocks of iron ore in the Chinese market will offset this shortage while demand is not very favorable.
Today, when it comes to the global steel products market, the word “global” is not very appropriate. There seems to be different behavior with different bases.
Weakening demand almost everywhere and falling commodity prices are sure to force mills to slow production, and the biggest issues facing the world’s steelmakers are production and profitability. The supply balance has been disrupted and in some countries, the flow of steel trade has been disrupted, both from a political point of view and from a business decision-making point of view.
The energy crisis in parts of the world, including the EU, in the fourth quarter of 2022 may undoubtedly stimulate increased demand, but it may not affect the entire global market. Because safeguards in areas deemed necessary to import steel products will discourage steel imports, especially from regions with competitive production advantages and low prices, such as Asia.
In this case, domestic producers in the country that owns the steel will naturally try to have more control over the domestic market and surrounding countries, which in itself will lead to higher production costs in that country. In some countries, steel will have double duty rates or higher prices in the domestic market and lower prices in the foreign market, but there will be obstacles to importation.
Optimism is the expectation and anticipation of the demand market in September. Low inventory levels on the market have given the mills hope for the fourth quarter of this year.
In addition, we have seen global barrel prices return from low levels to regular equilibrium prices. There are also reports that exports from Russian factories may be reduced due to a stronger currency, which could lead to prices shifting from very low and unhealthy levels to more stable levels.
Long products: increasing demand, expanded distribution of rebar
Global long product prices rose due to strong demand for steel ingots. But since the demand for wire rod is higher than for rebar, the price difference between the two products has widened.
World rebar and wire prices
Rebar prices were at $630-$650 per ton last week, as evidenced by the $600-$610 price increase the previous week, Metal Bulletin reported.
Russian and Ukrainian rebar prices are at $630-650 per ton, with price differences depending on volume and destination.
On the other hand, the price of Russian wire rod has risen sharply. Compared to the previous week, the price of steel has increased by $120-125, from the price range of $625-630 to $750 per barrel. ton.
In the rebar market, the spread is $80 to $100 per ton, compared to $10 to $20 previously.
Reasons for the price difference between rebar and steel wire
According to activists in the field, many manufacturers in different countries produce rebar, so the competition for this product is fierce. If there are few factories producing steel wire, many countries do not produce steel wire at all.
In addition, the demand for rebar is only from the construction industry, but wire rod is a product that is used by both the construction industry and the automotive industry and industrial machinery, so its demand is much higher than rebar.
All this has caused wire prices on the world market to rise more than rebar and to rise further. The price of Russian wire rod on the market is about $750 per tons, which is beyond what buyers can afford.
Ukrainian cords are sold on the market for between $680-700. Overall, the thread ended last week at $680-$700, up sharply from the previous week, in the $615-$630 range, according to Fastmarkets.
Russian wire rod is also rumored to be trading at $720-730 per tonne in unrecorded and unconfirmed trades. High ingot prices are believed by many to be the reason why producers deliberately raise steel prices. The daily price of steel ingots was $540 per ton, up $29 from the previous week, Metal Bulletin reported.
According to industry insiders, due to the sharp increase in the price of cast iron, some manufacturers have withdrawn from the sales market for steel ingots, and in addition to the high price of this raw material, its volume in the market has also decreased. Currently, manufacturers are more inclined to produce products with a higher return on investment, such as wire rod.
Intermediate steel products: Global ingot prices rise
The steel bullion price chart maintained an upward trend this week. Rumor has it that gold from Russia and Ukraine is trading at $580-$605.
Still, Turkey is the largest consumer of steel ingots in the CIS, having bought most of the ingots used as raw material for wire rods, according to Metal Bulletin.
A Ukrainian producer is said to have sold 10,000 tons of ingots for wire rods to a Turkish rolling mill for $590 per ton. ton, with a delivery date in February.
Buyers are powerless due to high prices
On the other hand, many commercial companies refuse to buy because the price is too high to buy. However, Russian steel ingots have buyers from the Far East at $600 per ton, about $40 more than the actual price. In addition, these buyers have accepted the terms of delivery in April.
Although these orders have yet to be registered, the above barrel prices appear to be appropriate for the South Asian country given the wild swings in Chinese prices. In particular, the price of rebar in China has risen sharply, reaching the highest value in nearly three years, and is still on an upward trend.
Global barrel prices have also followed an upward trend, so in one day from December 21 to December 22, 2020, barrel prices have reached $569 to $577. Ingot prices are expected to rise in the first quarter of 2021.
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