HRB400 is a kind of name of the new standard of reinforced, as one of the hot rolled ribbed steel bar. The name of the new standard for HRB400 reinforced, tertiary rebar for old said, as one of the hot rolled ribbed steel bar. In the construction industry, tertiary rebar is the last term.
Of the brand by HRB and number of hot rolled ribbed steel bar yield point of the minimum value. H, R, B Hot rolled (Hot rolled) respectively, ribbed (ribbed), steel bar (Bars) the first three words of English letters.
Classification of HRB400 -
Divided into HRB335 hot rolled ribbed bar (Numbers of 20 mnsi), HRB400 (the old number is 20 mnsiv, 20 mnsinb, 20 mnti), HRB500 three grades.
Fine grain hot-rolled reinforced its brands after the abbreviation of hot rolled ribbed steel bar and "Fine" (Fine), the first letter in English. Such as: HRBF335, HRBF400, HRBF500.
Have higher requirements of aseismatic structures for brand is: after the existing brand and E (for example: HRB400E, HRBF400E).
HRB400 - main purposes
Widely used in houses, Bridges, roads and other civil engineering construction.
HRB400 - leading producer
Rebar manufacturers in our country mainly in north and northeast, north China area such as shougang, tangshan, xuanhua, ChengGang, shanxi ZhongYang steel mills, baoding pury steel, northeast Westwood, north Taiwan, stroke, such as steel and so on, the two regions more than about 50% of the total output of rebar.
Rebar and light surface is the difference between a round bar with longitudinal and transverse ribs, usually with 2 longitudinal and cross rib of uniform distribution along the length direction. Belong to small section steel rebar, mainly used for reinforced concrete frame construction. In use requires a certain mechanical strength, bending deformation properties and welding performance. Production of raw materials of rebar steel billet calm smelting process in the carbon structural steel and low alloy structural steel, finished steel for hot rolling forming, is fire or hot rolling state delivery.
HRB400 - reverse bending performance
According to buyer's requirements, the rebar can reverse bending performance test.
Reverse bending test of curved heart diameter than the corresponding increase a rebar diameter bend test. Positively curved 45 degree first, and then reverse bending 23 degrees, reverse bending after 23 degrees. After reverse bend test, rebar bending parts surface shall not crack.
HRB400 - surface quality
Rebar surface permits can not have crack, scarring, and folding.
Rebar surface with convex block is allowed, but must not exceed the height of the horizontal rib, other defect depth and height of the rebar surface shall not be greater than their positions to allow the size deviation.
HRB400 - size, shape, weight, and allowable deviation
1. Nominal diameter range and recommend the diameter
Rebar nominal diameter in the range of 6 ~ 25 mm, standards recommended by the rebar nominal diameter is 6, 8, 10, 12, 16, 20, 25, 32, 40, 50 mm.
2. The ribbed steel plate surface shape and size of allowable deviation
Ribbed rebar cross rib shall meet the following basic requirements:
Axis transverse ribs with steel plate of beta should not be less than 45 degree Angle, when the Angle is not greater than 70 degrees, rebar relative to the direction of the horizontal rib on both sides should instead;
L cross rib and spacing shall not be greater than the rebar nominal diameter of 0.7 times;
Horizontal rib on the side and Angle on the surface of the rebar shall not be less than 45 degrees;
Rebar clearance between relative to the end of cross rib on both sides (including the longitudinal rib width) should not be greater than the sum rebar 20% of nominal circumference;
When the rebar nominal diameter is not more than 12 mm, relative costal area should not be less than 0.055; nominal diameter is 14 mm and 16 mm, relative costal area should not be less than 0.060; Nominal diameter greater than 16 mm, relative costal area should not be less than 0.065.
3. Length and allowable deviation
A, length: rebar usually according to the specified length delivery, specific delivery length should be indicated in the contract; rebar to volume delivery, each dish should be a rebar, allowing each group of 5% plate number (less than two sets can have two sets) consists of two rebar. Its diameter disc weight and plate shall be formulated by the supply and demand both sides talks things over.
B, the length of the allowable deviation: rebar according to scale the length of the delivery of the allowable deviation shall not be greater than + 50 mm.
C, bending and end: straight rebar bending change should not affect the normal use, the total curvature is not more than 40% of the total length of screw thread; Rebar ends should be cut integrity, local deformation shall not influence the use. 
HRB400 - need to detect project
Inspection items include: certificate number, rolling furnace number, grade, chemical composition (C, Si, Mn, P, V), tensile strength, yield point, elongation, relaxation rate, sectional area, product name, specification, quantity, delivery date, executive standard, receiving unit, etc. Only after inspection qualified can be for rebar, the acceptance of work.