Today, had been the day that whorl steel new GB applies, early the detailed rules that has released new GB in the beginning of the year, where is new GB of that whorl steel newly after all?
With GB/T 1499.2-2007 old standard photograph is compared, new standard is main made improvement, promotion from the following.
Addition smelt method is: Converter and smelt of electric arc furnace, can accept the fine outside furnace when necessary.
Added 600MPa class reinforcing steel bar
Hot-rolling takes common of costal region reinforcing steel bar to call whorl steel, use extensively at the construction work such as building, bridge, road. The basis builds the need of quality, excel in reinforcing steel bar also is being popularized energetically on policy in last few years. At present numerous company has studied give out 500/600 class reinforcing steel bar, formed on the market 400, 500, the whorl steel of level of 3 600 intensity.
The country waits in the United States, Canada, Korea, dosage of 400MPa whorl steel achieves 70% above, 500MPa also was achieved 25% ; The 500MPa class such as Germany, France, England achieved 70% above, raised the requirement to 600MPa class reinforcing steel bar at the same time.
As the promotion of social progress and quality demand, application of future of high strenth reinforcing steel bar is wide, those who erect rolled steel upgrade replacement also is inevitable trend. According to statistic, HRB400 is opposite at HRB335 but managing the dosage of 12% .
Add appropriately to weight deviation severe, do not allow answer test
Our country is the country with whorl steel the biggest dosage, new standard also is made to weight deviation add appropriately severe. The deviation of whorl steel weight of 12 norms of the φ in implementing a standard now is ± 7% , also add this appropriately severe rise to ± 6% . What the measurement technique in the standard carries out is to press group measure, measure itself to because sheet is raised,can avoid those who cause to measure as far as possible measure an error, measuring an error can do not have below the circumstance of oversight necessary answer check.
Increase metallographic organization to examine requirement and law of proved recipe of check of its form a complete set
This condition causes the market to pay close attention to the biggest is the craft that wear water, as decide hot-rolling reinforcing steel bar (advocate if will increase strength through adding alloying element) with the reinforcing steel bar that wear water (advocate if pass the craft that wear water to increase strength) according to, can avoid effectively to use copy of the reinforcing steel bar that wear water to risk hot-rolling reinforcing steel bar.
In the past, the reinforcing steel bar that wear water distinguishs very hard on building site with naked eye, when wearing water reinforcing steel bar to solder in need, because temperature lifts its crystal structure can expand, bring about then solder the intensity of place drops, can affect the quality of the building so.
After new GB is adjusted, as a result of the change of craft, cost of whorl steel production also will appear relatively rise substantially. After new GB is carried out, the microalloy element such as the main alloying element such as titanium of the manganese that the requirement in manufacturing technology joins, silicon, vanadium and vanadium is occupied than promotion.
In wearing water craft, with vanadium element 0.025-0.03% , manganese element 1.3-1.4% , silicon 0.4-0.5% , synthesis of alloy put together is 420 yuan about originally / ton, increase vanadium cost newly 230 yuan / ton. Domestic vanadium price begins to rise first year after year today oneself, at present vanadium price keeps strong and current as before quote of azotic vanadium alloy achieves 77-82 10 thousand tons / ton, vanadium iron price reports for duty 500 thousand / ton, relatively the beginning of the year rises respectively 218% with 163% . Because contain vanadium product value to rise considerably, bring about cost of new GB whorl to rise generally be in 200 yuan / ton above.
That is to say, after whorl steel executes new GB, because add vanadium craft, those who cause whorl steel cost carry litre, whorl steel and hot-rolling board the price difference that because craft difference is caused,coils is wiped basically to make the same score.
Difference has reached a snail price of the near future - 390, the estate that basically depends on be demand with whorl steel, capital construction and the car difference place that are demand with plank are caused.