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Pickling Principle of HUNGTHAI Color Steel Coil China

Pickling is HUNGTHAI Metal’s one of the important steps in making cold rolled steel coil, we provide you with high quality cold rolled steel coil.

The scales of iron oxide formed on the surface of the strip are insoluble in water, and when they are immersed in acid or sprayed on the surface, they undergo a series of chemical reactions with the acid. Due to the loose, porous and cracked properties of the iron oxide scale on the surface of carbon structural steel or low-alloy steel, and the repeated bending of the iron oxide scale on the pickling unit, these pores and cracks are further increased and enlarged, so the acid solution is in contact with While the iron oxide scale reacts chemically, it also reacts with the steel through cracks. Therefore, the pickling principle can be summarized into the following four aspects.

1. Dissolution
Various paste oxides in the iron oxide scale on the surface of the strip are dissolved in the acid solution to generate ferric and ferrous chlorides or sulfates that can be dissolved in the acid solution, thereby removing the iron oxide scale from the surface of the strip. This effect is generally called dissolution.

2. Mechanical peeling effect
In addition to the various oxides of iron, the iron oxide scale on the surface of the strip is also mixed with some metallic iron, and the iron oxide scale is porous, so the acid solution can pass through the gaps in the iron oxide scale. and produce a lot of hydrogen. The expansion pressure generated by this part of the hydrogen can separate the iron oxide scale from the surface of the strip. We call this reaction mechanical exfoliation.

3. Osmosis
The acid solution enters through the gap of the iron oxide scale and reacts with FeO. Since FeO and Fe2O3 are easy to react with the operator, the phenomenon that the iron oxide scale falls off due to the dissolution of the lower FeO in the acid occurs. This phenomenon is called osmosis.

4. Reduction
When metallic iron reacts with acid, hydrogen atoms are first produced. Part of the hydrogen atoms combine with each other to form hydrogen molecules, which promotes the separation of the iron oxide scale. The other part of the hydrogen atoms reduces the oxides and salts of high-valent iron to low-valent iron oxides and salts that are easily soluble in acid solutions by virtue of their reducing power.

Hungthai metal have a complete quality supervision system and professional production equipment, and our goal is to provide all customers with the highest quality steel coils.

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In November, cold rolled steel coil showed a weak balance between supply and demand, and the price center may move down again

Overview: In October, the price of cold-rolled steel coils showed a fluctuating downward trend, with prices falling by 215 yuan/ton month-on-month. From an inventory point of view, the level of depot depots from factories and warehouses was average, and social depots increased slightly again, and the pressure to depot depots was prominent; from a supply perspective, most steel mills ended their annual maintenance in October and some areas were relaxed due to “power curtailment”, and supply rebounded slightly. ; From the current market research situation, in November cold-rolled steel coil demand is difficult to pick up, the price center of gravity may fall again.

Overall review of the international market for cold rolled coils

China’s cold-rolled steel coil export prices fell slightly in October, with a month-on-month drop of US$23/ton. From market feedback, in late October, affected by the decline in domestic prices, export quotations fell, and export prices fell to around 991 yuan/ton, but export prices were still at a high level. From the data point of view, with the rise of resources in India and the Commonwealth of Independent States, China’s refrigeration resources have recently regained some advantages. In addition, the epidemic situation in Southeast Asia has improved somewhat recently. Terminal production and work resumed relatively smoothly. Some merchants resumed the procurement of cold coils. It is expected that China’s cold coil exports will improve to a certain extent in the short term. It is expected that the export price in October will remain within USD 1,000/ton. , Showing an oscillating trend.

 Raw material exports of cold-rolled steel coils

According to customs statistics, in September, the export volume of cold-rolled thin steel sheets and cold-rolled thin-width steel coils was 616,700 tons, a month-on-month decrease of 22,400 tons and a year-on-year increase of 376,500 tons; from the expected data, exports in October The volume continued to decline month-on-month, but the rate of decline may be significantly narrowed, reflecting the rebound in overseas demand. It is expected that exports will stop falling and stabilize in November.

 The difference between cold and hot spreads and cold plating spreads fluctuates

 In October, the price difference between hot and cold expanded slightly. As of the end of October, the price difference between hot and cold was 807 yuan/ton, an increase of 153 yuan/ton month-on-month; the spread of cold plating was 269 yuan/ton, and the month-on-month decrease 34 yuan/ton. Judging from the recent market situation, hot-rolled prices have fallen sharply, while cold-rolled prices have fallen slowly. It is expected that the cold-hot spread and the cold-plated spread will continue to fluctuate in the range in November.

In terms of cost: According to market research, the profit of long-flow cold-rolling production enterprises is maintained at 450-600 yuan/ton. In the case of reasonable profits, long-flow cold-rolling production enterprises are more enthusiasm for production; independent steel rolling enterprises currently maintain profits At 150 yuan/ton, the price of hot-rolled steel coil has dropped significantly recently, while the price of cold-rolled steel has been relatively strong, and the price difference between cold and hot steel has remained at 700-800 yuan/ton. Therefore, independent steel rolling enterprises in November are still enthusiastic about production while costs are falling. .

In November, the overall supply and demand of cold-rolled rolling stocks showed a weak balance. Factory warehouses and social warehouses may continue to increase. The overall inventory of cold-rolled steel coils may show an increase in warehouses. In the case of consumption falling short of expectations, the overall market mentality is more pessimistic. In summary, the center of gravity of cold rolled prices in November may fall again.

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China cancels tax rebates for cold-rolled coil and hot-dipped galvanization, but exporters still have a chance to make ends meet

The government announced to cancel export tax rebates for some steel products, including cold-rolled coil and galvanized steel, which is bad news for many importers all over the world. However, the impact on Chinese suppliers may be temporary, and so far, the long-awaited export tariff has not yet been announced.

State Taxation Administration, Ministry of Finance of the People’s Republic of China on Thursday announced to cancel the export tax rebates for 23 steel products from August 1, 2021. The published list includes galvanized color-coated steel materials, tinplate, some steel rails, steel pipes for the oil and gas industry, and the most sensitive tax rebate is cold-rolled coil and galvanization. After the cancellation of export tax rebates for most other finished steels (including hot-rolled coil) in April, it is more attractive for many foreign buyers to import cold-rolled coil and galvanized steel from China, because cold-rolled coil is much cheaper than hot-rolled coil.

Officials claimed that the reason for this move was that the government intended to crack down on steel mills’ enthusiasm to further expand crude steel production and force them to focus on producing high-quality products. However, a Chinese trader said: “It seems that China does not like people who do steel business in this country.” And on July 29, another major trader said: “All our recently exported cold-rolled coils are at the buyer’s full risk, so we will not lose money now. But this will be a huge problem for our customers and the whole China.”

Most Chinese steel mills and traders have suspended the provision of cold-rolled coil and galvanized steel in the international market, because they need time to ask for information. Some suppliers facing external markets have increased their quotations of cold-rolled coil and galvanized steel by $50 and $30 per ton from last week’s prices, and to $980-$1000 FOB and $1010-$1030 FOB per ton respectively. Nevertheless, a major Chinese state trader said: “It seems that we can still export our products, because Japan’s cold-rolled coil is still about $60 per ton more expensive than China, and our galvanized steel is $120 per ton cheaper than India.” “I am not sure about all foreign markets, but South America will definitely be our big customers due to few choices,” another trader expressed his opinion. The head of the export department of a large Chinese steel company said: “The United States and the European Union will suffer the most, because they will have to accept higher prices from Taiwan, Vietnam and other countries and regions after China cancels the tax rebates.”

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