"Steel for Reinforced Concrete Part 2: Hot-rolled Ribbed Reinforcement Bars" was approved and issued by the General Administration of Quality Supervision, Inspection and Quarantine and the National Standardization Management Committee on February 6, 2018. The standard number is GB/T1499.2-2018, which will be put into effect on November 1, 2018. The revised standard of hot-rolled steel bar has reached the international advanced level. The adjustment of smelting method provides technical support for striking and banning floor bar steel. The requirement of metallographic structure inspection and its matching inspection methods are added as the basis for judging hot-rolled steel bar and water-piercing steel bar, which can effectively avoid imitating hot-rolled steel bar with water-piercing steel bar. With the implementation date of the "new standard" approaching gradually on November 1, 2018, the changes of steel quantity and alloy consumption involved return to the market. This paper makes the following judgments on the hot spots of market concern.

(1) The new standard involves the calculation of the number of reinforcing bars requiring modification; (2) the incremental interval value of manganese alloy; (3) the incremental numerical prediction of vanadium alloy; (4) whether there will be substitution of each other when the alloy price reaches a certain peak; (5) the factors affecting the alloy price and supply and demand in the later period.

I. Estimation of Vanadium Consumption Involving the Value of Reinforcement Bars

In 2017, V alloys used in steel market, with a volume of 75,000 tons of V2O5 and 42,000 tons of pure vanadium, were applied in threaded steel with an average absorptivity of 0.93 and a total of 39,000 tons of pure vanadium. According to the statistics of China Steel Association, the proportion of HRB400, HRB500 and HRB600 in threaded steel is about 77%, 20% and 1% respectively. The qualified rate of vanadium in HRB400 and HRB500 is assumed to be the same and applied in the lowest proportion. The situation of vanadium in HRB600 is completely conformable. The established formula is 0.03*0.77*200+0.06*0.2*200+0.1*0.01*200=722,000 tons. Therefore, this proportion should be the proportion of the conforming threaded steel bar. The established formula is 0.03 * 0.77 * X + 0.06 * 0.2 * X + 0.1 * 0.01 * X = 3.9, then X = 108 million tons. In 2017, the output of rebar is about 200 million tons, that of vanadium-containing rebar is about 108 million tons (fully qualified), that of niobium-containing rebar and niobium-vanadium mixed rebar is about 10 million tons, and that of water-penetrating rebar is about 80 million tons. Among vanadium-containing steel bars, 60% are fully compliant, 26% are low vanadium and vanadium-containing micro-penetrating steel bars. According to the comprehensive calculation, the total amount of vanadium-containing steel bars in 2017 is about 129 million tons. With some pure niobium bars, the total amount of microalloyed steel bars is about 130 million tons, and 2% of threaded steel bars is Q235, with a total amount of about 4 million tons. It is expected that this amount will be converted to the new standard HRB300 steel bars. The limit value of reinforcement is about 67 million tons.

2. The manganese alloy increment calculation shows that 40% (low value) and 80% (high value) of 67 million tons of water penetrating steel bars are hot rolled. According to the proportion, HRB400 is 77%, the average manganese content of steel per ton is increased by 0.7%, HRB500 is 20%, and the average manganese content of steel per ton is increased by 0.4%. In the compliance products, manganese index is basically qualified and need not be revised. However, due to the insufficient vanadium content of some products, there may be a situation of increasing manganese content and increasing its physical properties. Its increment is estimated to be 0-15,000 tons of manganese. Comprehensive calculation shows that after the implementation of the new standard, the increment of demand for low-value "manganese" is about 185-201,000 tons, while that for Silicon-manganese 6517 is about 2836-3096,000 tons, with an average monthly increment of about 24-26,000 tons. The incremental demand for high-value "manganese" is about 3318-347,000 tons, and that for Silicon-manganese 6517 is about 5676-592,800 tons, with an average monthly increment of about 473-494,000 tons.

Table 1: Estimation of Manganese Alloy Increment

3. Calculation of Vanadium Alloy Increment

Hot rolling process is carried out in 40% (low value) and 80% (high value) of 67 million tons of water penetrating steel bar. According to the proportion, HRB400 is 77%, the average vanadium content per ton steel increases by 0.03%, HRB500 is 20%, and the average vanadium content per ton steel increases by 0.06%. In the original vanadium-containing steel bar, there is a phenomenon of micro-penetration water with insufficient vanadium content. Among them, the micro-penetration water standard of HRB400 is expected to increase by 0.01%, the micro-penetration water standard of HRB500 is expected to increase by 0.02%, and the increment is about 4281 tons of vanadium. After the implementation of the new standard, the increment of demand for low-value "vanadium" is about 13688 tons, assuming that the average absorption rate is 93% and the reduction of vanadium pentoxide is about 26,000 tons. The incremental demand for high-value "vanadium" is about 23095 tons, assuming that the average absorption rate is 93% and that vanadium pentoxide is about 44,000 tons.

Table 2: Estimation of Vanadium Alloy Increment

IV. Non-negligible Substitution Phenomena of Alloys

In the initial stage of the implementation of the new standard for threaded steel, the supervision of the upper level is bound to be unprecedented, but because the new standard does not calibrate the chemical elements of the threaded steel, it only provides guidance on the physical properties: macro-metallographic, Vickers hardness of cross-section and micro-structure. Therefore, in view of the current raw material cost and supply situation, it is not excluded that some steel mills may try to substitute and make up for each other by other alloys. By comparing the current production cost of raw materials, "vanadium", "niobium", "manganese" and "titanium" alloys have their feasibility and shortcomings.

Table 3: Cost Note of Alloys in Tons of Steel: Cost of Vanadium and Niobium in Tons of Steel does not need to be recalculated and is substitutable.

1. "Vanadium" is widely used in major steel plants as the additive with the highest production stability and the best strengthening effect in hot-rolled steel bars. At the same time, due to the poor market efficiency in 15-16 years, environmental protection has been continuously pressurized since 17 years, the import of vanadium slag has been completely prohibited, and the market supply is seriously inadequate under various pressures; the downstream steel market bans the bar steel, product upgrading and the demand for construction steel. The market is very good. Under the contradiction between supply and demand, the price of vanadium keeps rising. Under the new standard of reinforcing bars, insufficient supply has become an inevitable trend. In order to maintain the quality of steel products, steel mills have to purchase raw materials at high prices or choose other alloys to replace them. 2. The cost of "vanadium" per ton of steel is about 180 yuan, and "niobium" is regarded as the cost of "vanadium" per ton of steel.