As one of the most basic and widely used products in the iron and steel industry, carbon steel coils have penetrated into many core fields of the national economy such as construction, manufacturing, and logistics, relying on their advantages of controllable cost, strong performance adaptability, and convenient processing, becoming a "cornerstone" material supporting the operation of the industrial system. With the iterative upgrading of production technology and the continuous refinement of market demand, the carbon steel coil industry is undergoing a transformation from scale expansion to quality improvement, and from standardized production to customized services. Its technological innovation and industrial development trend are directly related to the upgrading pace of downstream industries and the process of high-quality national industrial development.

I. Core Cognition of Carbon Steel Coils: Definition, Classification and Core Characteristics

Carbon steel coils are steel products made of carbon steel, processed and formed by hot rolling or cold rolling processes, and coiled into a coil shape. Their core components are mainly iron and carbon, supplemented by a small amount of elements such as manganese and silicon, without or with a very small amount of alloying elements. Therefore, compared with alloy steel coils, they have more cost advantages, and are currently the steel category with the largest usage and the widest application.

According to the different production processes, carbon steel coils are mainly divided into two categories: hot-rolled carbon steel coils and cold-rolled carbon steel coils. The two have different performances and uses, adapting to the needs of different scenarios:

• Hot-rolled carbon steel coils: Adopting high-temperature rolling process, they have high production efficiency and low cost. The steel surface is with oxide scale, moderate hardness and good toughness. They can be directly used in scenarios such as building structures, pipeline manufacturing, and mechanical parts processing, and can also be used as raw materials for cold-rolled carbon steel coils. Their specifications cover a wide range, which can meet the diverse needs of different industries for steel thickness and width.

• Cold-rolled carbon steel coils: Taking hot-rolled carbon steel coils as blanks, after subsequent treatments such as cold rolling, annealing, and pickling, they have smooth and clean surface, high dimensional accuracy, and uniform thickness, with better toughness and plasticity. They can be further processed into stamping parts, home appliance casings, auto parts, etc., and are widely used in the field of high-end manufacturing.

The core characteristics of carbon steel coils are concentrated in "strong adaptability, high cost performance, and flexible processing": their strength can be adjusted according to the carbon content, from the easy stamping and welding of low-carbon steel coils to the high strength and wear resistance of high-carbon steel coils, which can match the performance needs of different downstream scenarios; at the same time, compared with stainless steel coils and alloy coils, carbon steel coils have easy-to-obtain production raw materials, mature production processes, and significant price advantages, making them the preferred material for mid-to-low-end manufacturing and infrastructure construction; in addition, carbon steel coils can be formed through various processing methods such as cutting, bending, welding, and stamping, adapting to the production needs of different products and further expanding their application boundaries.

II. Technological Innovation: Solving Pain Points and Promoting the Quality Upgrade of Carbon Steel Coils

The quality and performance of carbon steel coils depend on the scientificity and refinement of the production process. In the past, the traditional production process had many pain points. For example, when rolling carbon steel blanks with 200*200mm cross-section, limited by factors such as incoming material size, pass design, and tooling guides, it was easy to have bamboo-like fluctuations on the surface of small-size finished products and excessive dimensions of large-size finished products, which seriously affected the product qualification rate and application experience. In recent years, with the continuous breakthrough of production technology, the production process of carbon steel coils has achieved comprehensive innovation. Every link from blank processing to finished product inspection has been refined and optimized, promoting a qualitative leap in product quality.

A mature modern carbon steel coil production process mainly includes nine core steps, with each link closely connected and strictly controlled:

1. Blank Preparation: Hoist square steel blanks, stack them in a "well" shape according to layers, arrange them strictly in the order of furnace charging, and comprehensively inspect the surface quality of the steel blanks. Grind and peel the blanks with defects; among them, the blanks of cold heading steel grades need additional chamfering and grinding to completely remove surface defects, laying the foundation for subsequent rolling.

2. Heating Treatment: Strictly control the heating temperature and time. The temperature of the heating section is maintained at 980~1050℃, the temperature of the soaking section is controlled at 1020~1100℃, and the heating time does not exceed 3 hours to ensure uniform heating of the steel blanks and improve the plasticity and forming effect during the rolling process.

3. Descaling Treatment: Adopt high-pressure water descaling technology with a high-pressure water pressure of not less than 18MPa to effectively remove the oxide scale on the surface of the steel blanks, avoiding the oxide scale being embedded into the steel surface during the rolling process and affecting the surface quality and performance of the products.

4. Pass Rolling: Gradually roll the steel blanks from coarse to fine through rough rolling, first intermediate rolling, and second intermediate rolling in turn. Among them, the rough rolling includes 5 passes, the first intermediate rolling includes 6 passes, and the second intermediate rolling includes 4 passes. During the rolling process, the blanks are always transformed between elliptical and circular shapes, and finally form semi-finished products with circular cross-sections. At the same time, strictly control the elongation coefficient (1.02~1.45) and spread coefficient (0.25~0.7) of each pass, and the running speed of the steel blanks changes from slow to fast, ranging from 1.9m/s to 20m/s to ensure rolling accuracy.

5. Pre-finishing Rolling: Use flying shears to cut off the irregular parts of the head and tail of the steel bar after the second intermediate rolling, then enter the pre-finishing rolling link, and after 4 passes of rolling, further refine the steel size and improve the product accuracy.

6. Three-stand Compact Mill Rolling: Use flying shears again to remove the irregular head and tail of the steel bar after pre-finishing rolling, then enter the three-stand compact mill for 3 passes of rolling, and finally obtain qualified wire rods. The core innovation of this link is that the finished pass is designed according to the thermal expansion coefficient of carbon steel, the guide adopts a four-guide wheel device, and the guide wheel is changed from V-type to R-type, which effectively solves the problems of dimensional deviation and surface defects in the traditional process.

7. Coiling: Use a coiler to convert the wire rod into a circular large coil. The coiling temperature is strictly controlled at 850~920℃. In some scenarios, a water-through cooling link will be added after rolling, using Φ30, Φ50, Φ70 water-cooled pipes for cooling to ensure that the coil temperature meets the standard and avoid deformation during coiling.

8. Controlled Cooling Treatment: Precisely control the steel cooling speed through a combination of water quenching cooling, air cooling, and heat preservation slow cooling, optimize the internal structure of the steel, and improve the core performance such as toughness and strength of the product.

9. Inspection and Packaging: Conduct comprehensive quality inspection on the finished carbon steel coils, focusing on checking indicators such as dimensional accuracy, surface quality, and mechanical properties. Only qualified products can be packaged and stored in the warehouse to ensure that the products entering the market meet the national standard requirements.

The effect brought by technological innovation is very significant: compared with before the improvement, the improved process not only realizes the comprehensive expansion of rolling specifications, the rolled steel grades are expanded from stainless steel + low-standard carbon steel to stainless steel + carbon steel (including high-standard cold heading steel), the blank cross-section covers 150*150mm and 200*200mm, and the rolling specifications are expanded from 24~31 to 14~40 (including 0.5 specifications); the product accuracy is also greatly improved, the bamboo-like defects on the surface of products with ≤23 specifications are completely eliminated, and the C-grade product rate of each specification is increased to more than 89%, which completely solves the pain points of the traditional process and provides quality guarantee for downstream high-end applications.

III. Market Status: Supply and Demand Optimization and Business Model Iterative Upgrade

In recent years, China's carbon steel coil market has shown a development trend of optimized supply and demand structure, reshaped competition pattern, and accelerated technological innovation, and the industry as a whole is transforming towards high-quality development. In terms of market scale, the scale of China's carbon steel coil and plate market reached 180 million tons in 2024, an increase of 3.2% compared with 2023, and the total industrial output value was about 820 billion yuan. The stable market demand provides a solid support for the industry development.

On the supply side, the industry concentration continues to increase. The output of the top ten iron and steel enterprises accounts for 65%, an increase of 8 percentage points compared with 2020, and the capacity utilization rate is maintained at a reasonable range of 82%, effectively avoiding the problem of overcapacity. At the same time, the supply structure is constantly optimized, the proportion of high-end products is increased to 40%, the intensity of technological innovation investment reaches 2.1%, the networking rate of digital equipment reaches 75%, and intelligent manufacturing and green manufacturing have become the mainstream of the industry development. More and more enterprises are increasing investment in process research and development, optimizing production processes, and promoting the development of carbon steel coil products towards high precision, high toughness and customization.

On the demand side, the structure presents diversified and high-end characteristics, mainly concentrated in three major fields: first, the construction industry, with a consumption of about 85 million tons, accounting for 45%, mainly used for housing construction, infrastructure construction, etc. With the advancement of new urbanization and the acceleration of urban renewal, the demand for carbon steel coils remains stable; second, the manufacturing industry, with a demand of 72 million tons, accounting for 38%, among which the demand for automotive steel increased by 25%, the demand for high-end products in the home appliance industry accounted for 70%, and the demand in the new energy field increased by 45%, becoming the core driving force for the growth of carbon steel coil demand; third, the export market, with an export volume of 18 million tons, the products are transforming towards high-end, and the international market competitiveness is continuously improving.

In terms of business model, the carbon steel coil market is transforming from traditional trade to digital comprehensive services. The traditional multi-level distribution model is gradually optimized. Large enterprises have begun to build a "manufacturing + service" system, with a customization ratio of 35%, value-added service income accounting for 25%, the scale of supply chain finance business reaching 850 billion yuan, and the transaction scale of e-commerce platforms exceeding 2.8 trillion yuan. Enterprises are no longer limited to simple product sales, but provide customers with integrated solutions such as design, processing, logistics, and distribution, and optimize supply chain management through digital means to improve transaction efficiency and customer experience.

The price formation mechanism is also becoming more and more perfect. On the basis of cost pricing, it integrates multiple factors such as brand premium, futures guidance, and policy impact. At present, the total cost of carbon steel coils is 4200-4800 yuan/ton, the premium rate of well-known brands reaches 28%, and environmental protection cost has become an important component, about 150-200 yuan/ton. Environmental compliance capacity has gradually become one of the core competitiveness of enterprises.

IV. Industry Trends: Green and Intelligent, Empowering High-Quality Industrial Development

Looking forward to 2026 and the next five years, the carbon steel coil industry will continue to develop around the four directions of "greenization, intelligence, high-endization, and diversification", the industry pattern will be further optimized, and the industrial value will continue to increase. Combined with the industry development rules and policy orientation, the carbon steel coil industry will mainly show three development trends in the future:

First, the green transformation will continue to deepen, and environmental protection will become the core competitiveness of the industry. Driven by the "carbon peak and carbon neutrality" goals, iron and steel enterprises will increase green investment, the environmental protection investment is expected to grow to 150 billion yuan, and the proportion of environmental protection cost will increase to 2.5%. Enterprises will further optimize production processes, promote clean production technologies, strengthen scrap recycling and reuse, waste heat power generation, water resource recycling, etc., promote the full-process greenization of carbon steel coil production, and reduce carbon emissions and pollutant emissions. At the same time, green supply chain management capacity will become an important consideration for enterprise cooperation, and ESG rating will affect the market competitiveness of enterprises.

Second, the penetration of intelligent manufacturing will accelerate, and production efficiency and product quality will continue to improve. It is expected that by 2026, the popularization rate of intelligent manufacturing in the iron and steel industry will reach 80%, the digital penetration rate will exceed 85%, and the industrial Internet platform will realize in-depth collaboration between the upstream and downstream of the industrial chain, realizing the full-process intelligent management from demand forecasting, production planning to delivery services. Through technologies such as artificial intelligence, the Internet of Things, and blockchain, optimize the rolling process, control production parameters, further improve product dimensional accuracy and performance stability, and at the same time reduce production energy consumption and labor costs, and promote the transformation of production mode towards flexibility and personalization.

Third, the high-endization of products and the diversification of applications will proceed in parallel, and the market demand will continue to upgrade. With the transformation of downstream manufacturing to high-end, the performance requirements of carbon steel coils in fields such as automobiles, home appliances, and new energy are constantly improving. The proportion of high-end products will increase to 50%, and the gross profit rate of high-end products will remain at 18-25%. At the same time, with the development of emerging fields such as urban renewal, infrastructure construction, and low-altitude economy, the application scenarios of carbon steel coils will be further expanded, the customized demand will continue to increase, and enterprises will focus on segmented markets, develop targeted products, and enhance their differentiated competitive advantages.

In addition, international development will become an important growth direction for high-quality enterprises. It is expected that by 2026, the proportion of overseas revenue of Chinese iron and steel enterprises will increase to 25%. Enterprises will realize global resource allocation through overseas investment and construction of factories, technology export, brand authorization, etc., and improve their international market competitiveness. At the same time, the industry competition will shift from price competition to technology competition, brand competition, and service competition, and R&D investment will continue to increase, promoting the continuous breakthrough of process technology and injecting new momentum into the high-quality development of the industry.

V. Conclusion

As a basic material of the industrial system, the technological innovation and industrial development of carbon steel coils are directly related to the stable operation of the national economy and the upgrading of downstream industries. From the prominent pain points of the traditional process to the comprehensive innovation of the modern process, the product quality of carbon steel coils has achieved a qualitative leap; from scale expansion to supply and demand optimization, the industry development model has realized the transformation from "quantitative accumulation" to "qualitative improvement".

In the future, with the continuous penetration of green manufacturing and intelligent manufacturing technologies, and the continuous upgrading of downstream market demand, the carbon steel coil industry will usher in a broader development space. Enterprises need to focus on technological innovation, product upgrading and service optimization, deepen segmented markets, enhance core competitiveness, promote the transformation of the carbon steel coil industry towards high-quality development, and provide a more solid material support for China's industrial modernization drive.