Definition

That is the new standard name for HRB500 steel, grade four steel as the old name, as a kind of hot rolled ribbed bar. In the construction industry, four screw steel is the old saying.

Hot rolled ribbed steel grades by HRB and number of yield points minimumcomposition. H, R, B respectively (Hotrolled), hot rolled ribbed steel bar(Ribbbed), (Bars) the three word's first letter English.

Classification

Hot rolled ribbed steel bar is divided into HRB335 (the old number is 20MnSi),HRB400 (the old No. 20MnSiV, 20MnSiNb, 20Mnti), HRB500 three brands.

Hot rolled bars of fine grains in the grades of hot rolled ribbed bar after Englishabbreviation "fine" English (Fine) the first letter. Such as: HRBF335, HRBF400,HRBF500.

A suitable grade higher requirements for seismic structures: add E in the existing brands after (for example: HRB400E, HRBF400E

The main purposes

HRB500 grade steel in strength, ductility, high temperature resistance, low temperature performance and seismic performance and fatigue performanceare better than HRB400 has greatly improved, mainly used in high-rise and super high-rise building, long span bridges, high standards of construction, is an international engineering standards recommended actively and has been widely used in developed countries products, it shows that the application ofpractice HRB500 steel works, can save a lot of steel, and has obvious economic benefit and social benefit.

The main origin

Screw thread steel producers in China are mainly distributed in North and northeast, North China area such as Shougang, Tang Gang, Xuan Steel,bearing steel, Shanxi Zhongyang steel plant, Baoding Purui the steel, the northeast area such as resistant, Tai, realize, these two areas account for about 50% of the total output in the screw thread steel.

The difference between the screw thread steel and round steel bar is provided with longitudinal ribs and transverse ribs surface, usually with two longitudinalribs and transverse ribs along the length direction of the uniform distribution.Screw thread steel belongs to the small steel steel, mainly used in reinforced concrete building components of the skeleton. In use requires a certainmechanical strength, bending deformation properties and process of welding performance. Screw thread steel billet production raw material for the carbon structure steel smelting processing sedation or low alloy structural steel,finished steel for hot rolling, normalizing or hot-rolled state of delivery.

Advantage

Nationwide, the annual if 20000000 t two screw thread steel is four level(HRB500) to replace, can save more than 5000000 t screw thread steeldosage. Equivalent to an annual consumption of iron ore 4000000 ~800 million T, save standard coal 1670000 ~335 million T, less consumption of fresh water 9600000 ~1740 million m3, to reduce dust emissions of sulfur dioxide emissions reduction of 750~1500t, 625~1250t, energy saving and emission reduction effectiveness is huge, consistent with the low carbon environmental protection concept of current international society pay more and more attention.

The promotion of the work

In order to make better performance, more economical and four screw steelproducts of low carbon environmental protection at home and rapidly applied,gradually to replace the two screw steel low level, should do the following aspects of work:

1 wide publicity to introduce four screw steel composition, properties and their own advantages, strengthen the construction design institute relevant indexes of four screw steel chemical composition, mechanical properties and welding performance of the understanding, promote the use of the design of the construction project, to lay a solid foundation for the four screw steel market promotion.

Each of the 2 key projects on strengthening highway, railway, bridge, and a series of infrastructure projects, do a good job of key projects of the bidding work, the realization of the four screw steel supply breakthrough from thelarge-scale key projects, the formation of a demonstration effect on other common construction project and the real estate industry, and graduallypenetrated into all fields of thread steel application, so as to fully replace thelow grade screw thread steel.