First, rebar
In the construction industry, grade II rebar and grade III rebar are known in the past. In the new standard, grade II rebar is called HRB335, and grade III rebar is called HRB400.
The grades of hot-rolled ribbed bars consist of HRB and the minimum yield point of the grade. H, R, and B are the English first letters of Hotrolled, Ribbbed, and Bars. Hot-rolled ribbed steel bars are classified into HRB335 (old name is 20MnSi) and HRB400 (brand name is 20MnSiV, 20MnSiNb, 20MnTi). Under normal circumstances, the theoretical weights of these types of steel bars are the same when the nominal diameter and length are equal.
Reinforced concrete reinforcement refers to straight or rod-shaped steel used for reinforcement of reinforced concrete. Its appearance is divided into two kinds, light round steel bar and deformed steel bar. The delivery status is straight bar and round bar. The light round bar is actually a small round steel and coil of ordinary low carbon steel. Deformed rebar is a surface ribbed rebar, usually with two longitudinal ribs and transverse ribs that are evenly distributed along the length. The lateral ribs are spiral, herringbone and crescent shaped. It is expressed in millimeters of nominal diameter. The nominal diameter of the deformed bar corresponds to the nominal diameter of the round bar with equal cross section. The nominal diameter of the steel bars is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, and 40 mm. Steel types: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Reinforced steel is mainly subjected to tensile stress in concrete. Because of the effect of ribs, deformed steel bars have a greater ability to bond with concrete and can therefore better withstand the effects of external forces. Reinforcing steel is widely used in various building structures, especially large-scale, heavy-duty, light-weight thin-walled and high-rise building structures. Tianhai Iron and Steel Co., Ltd. has been engaged in secondary and tertiary rebar, precision rolled rebar, and wire rod sales for 20 years. The most professional rebar suppliers in South China
Product Standards: (GB1499-1991, BS4449:1988)
Specifications: 8,10,12,14,16,18,20,22,25,28,32,36,40,50mm
New vanadium-bearing III grade rebars (20MnSiV, 400Mpa) incorporate vanadium, niobium, titanium and other alloys in the production process. Compared with ordinary grade II steel bar, they have the advantages of high strength, good toughness, good welding performance and good shock resistance. . In the developed markets of Europe and other developed countries, Grade III rebar accounts for 80% of the total rebar. In 1995, the former Ministry of Metallurgy and the Ministry of Construction jointly issued a document to promote the application, the Ministry of Construction will be the new tertiary rebar technology conditions into the national standard GBJ10-89 "Concrete Structural Design Specification."
The difference is mainly:
1. Different types of steel (different chemical composition). HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel is 20MnSiV or 20MnSiNb or 20MnTi;
2. With different strengths, the tensile and compressive design strength of HRB335 steel is 300MPa, and the tensile and compressive design strength of HRB400 steel is 360MPa.
3. Due to the difference in the chemical composition and ultimate strength of the steel bars, there are also differences in toughness, cold bending, fatigue resistance, and other properties. The theoretical weights of the two types of steel bars are the same when the nominal diameter and length are equal. The requirements for the length of the anchorage of the two steel reinforcements in concrete are not the same. The anchorage length of the steel bar is related to the tensile strength of the steel bar, the tensile strength of the concrete and the shape of the steel bar. Let us tell you a formula: The length of anchorage of tensile reinforcement in concrete is L=a×(f1/f2)×d. In the formula f1 is the tensile design strength of the steel bar; f2 is the tensile design strength of the concrete; a is the steel bar form factor, the smooth steel bar takes 0.16, the ribbed steel bar takes 0.14; d is the nominal diameter of the steel bar. In addition, when the rebar is HRB335 and HRB400 and its diameter is greater than 25mm, the anchorage length should be multiplied by a correction factor of 1.1. In the seismic zone, a coefficient greater than 1 should be multiplied by the earthquake resistance rating. The anchorage length of the compression rebar in the concrete is 0.7 times the anchorage length of the tensioned rebar.
Advantages of Vanadium Class III Threaded Reinforcement
A. Economy: Due to its high strength, the use of new grade III rebar can save 10-15% of steel compared to grade II rebar, thus reducing construction costs.
B, high strength, good toughness: the use of micro-alloying treatment, the yield point of more than 400Mpa, tensile strength of 570Mpa above, respectively, compared with the level II rebar increase of 20%.
C. Seismic resistance: The vanadium-containing rebar has high bending resistance, aging performance, high low-cycle fatigue performance, and its seismic performance is significantly better than that of the grade II rebar.
D, easy to weld: As the carbon content ≤ 0.54%, welding performance, adapt to a variety of welding methods, the process is simple and convenient.
E. Convenient construction: The use of new Grade III rebar has increased the construction clearance and provided a guarantee for construction convenience and construction quality.
Second, the difference between rebar and round steel
In construction engineering, round bar and rebar are the popular names for different types of rebar. The differences between them are mainly the following five points:
1. Different shapes. The outer surface of the round steel is smooth; the outer surface of the threaded steel has helical ribs.
2. Different production standards. In the current standard, the round bar refers to HPB235 grade steel bar, and its production standard is "refined hot-rolled smooth steel bar for reinforced concrete" (GB13013); rebar steel generally refers to HRB335 and HRB400 grade steel bars, and its production standard is "reinforced concrete Hot Rolled Ribbed Bar (GB1499).
3. Different strengths. The design strength of the round bar (HPB235) is 210 MPa; the strength of the rebar is higher than that of the round bar, the design strength of the HRB335 is 300 MPa, and the design strength of the HRB400 is 360 MPa.
4. Different types of steel (different chemical composition). Round bar (HPB235) is a carbon steel, steel is Q235; screw steel is a low alloy steel, HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel is 20MnSiV or 20MnSiNb or 20MnTi;
5. Physical and mechanical properties are different. Due to the differences in the chemical composition and strength of the steel bars, they differ in physical and mechanical properties. The round steel has better cold bending performance and can be used as a 180-degree hook. The rebar can only be used as a 90-degree straight hook. The round steel has good weldability and can be used with ordinary carbon electrodes. The rebar must be used with low Alloy electrode; Rebar has better toughness and fatigue resistance than round steel.
In the construction industry, grade II rebar and grade III rebar are known in the past. In the new standard, grade II rebar is called HRB335, and grade III rebar is called HRB400.
The grades of hot-rolled ribbed bars consist of HRB and the minimum yield point of the grade. H, R, and B are the English first letters of Hotrolled, Ribbbed, and Bars. Hot-rolled ribbed steel bars are classified into HRB335 (old name is 20MnSi) and HRB400 (brand name is 20MnSiV, 20MnSiNb, 20MnTi). Under normal circumstances, the theoretical weights of these types of steel bars are the same when the nominal diameter and length are equal.
Reinforced concrete reinforcement refers to straight or rod-shaped steel used for reinforcement of reinforced concrete. Its appearance is divided into two kinds, light round steel bar and deformed steel bar. The delivery status is straight bar and round bar. The light round bar is actually a small round steel and coil of ordinary low carbon steel. Deformed rebar is a surface ribbed rebar, usually with two longitudinal ribs and transverse ribs that are evenly distributed along the length. The lateral ribs are spiral, herringbone and crescent shaped. It is expressed in millimeters of nominal diameter. The nominal diameter of the deformed bar corresponds to the nominal diameter of the round bar with equal cross section. The nominal diameter of the steel bars is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, and 40 mm. Steel types: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Reinforced steel is mainly subjected to tensile stress in concrete. Because of the effect of ribs, deformed steel bars have a greater ability to bond with concrete and can therefore better withstand the effects of external forces. Reinforcing steel is widely used in various building structures, especially large-scale, heavy-duty, light-weight thin-walled and high-rise building structures. Tianhai Iron and Steel Co., Ltd. has been engaged in secondary and tertiary rebar, precision rolled rebar, and wire rod sales for 20 years. The most professional rebar suppliers in South China
Product Standards: (GB1499-1991, BS4449:1988)
Specifications: 8,10,12,14,16,18,20,22,25,28,32,36,40,50mm
New vanadium-bearing III grade rebars (20MnSiV, 400Mpa) incorporate vanadium, niobium, titanium and other alloys in the production process. Compared with ordinary grade II steel bar, they have the advantages of high strength, good toughness, good welding performance and good shock resistance. . In the developed markets of Europe and other developed countries, Grade III rebar accounts for 80% of the total rebar. In 1995, the former Ministry of Metallurgy and the Ministry of Construction jointly issued a document to promote the application, the Ministry of Construction will be the new tertiary rebar technology conditions into the national standard GBJ10-89 "Concrete Structural Design Specification."
The difference is mainly:
1. Different types of steel (different chemical composition). HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel is 20MnSiV or 20MnSiNb or 20MnTi;
2. With different strengths, the tensile and compressive design strength of HRB335 steel is 300MPa, and the tensile and compressive design strength of HRB400 steel is 360MPa.
3. Due to the difference in the chemical composition and ultimate strength of the steel bars, there are also differences in toughness, cold bending, fatigue resistance, and other properties. The theoretical weights of the two types of steel bars are the same when the nominal diameter and length are equal. The requirements for the length of the anchorage of the two steel reinforcements in concrete are not the same. The anchorage length of the steel bar is related to the tensile strength of the steel bar, the tensile strength of the concrete and the shape of the steel bar. Let us tell you a formula: The length of anchorage of tensile reinforcement in concrete is L=a×(f1/f2)×d. In the formula f1 is the tensile design strength of the steel bar; f2 is the tensile design strength of the concrete; a is the steel bar form factor, the smooth steel bar takes 0.16, the ribbed steel bar takes 0.14; d is the nominal diameter of the steel bar. In addition, when the rebar is HRB335 and HRB400 and its diameter is greater than 25mm, the anchorage length should be multiplied by a correction factor of 1.1. In the seismic zone, a coefficient greater than 1 should be multiplied by the earthquake resistance rating. The anchorage length of the compression rebar in the concrete is 0.7 times the anchorage length of the tensioned rebar.
Advantages of Vanadium Class III Threaded Reinforcement
A. Economy: Due to its high strength, the use of new grade III rebar can save 10-15% of steel compared to grade II rebar, thus reducing construction costs.
B, high strength, good toughness: the use of micro-alloying treatment, the yield point of more than 400Mpa, tensile strength of 570Mpa above, respectively, compared with the level II rebar increase of 20%.
C. Seismic resistance: The vanadium-containing rebar has high bending resistance, aging performance, high low-cycle fatigue performance, and its seismic performance is significantly better than that of the grade II rebar.
D, easy to weld: As the carbon content ≤ 0.54%, welding performance, adapt to a variety of welding methods, the process is simple and convenient.
E. Convenient construction: The use of new Grade III rebar has increased the construction clearance and provided a guarantee for construction convenience and construction quality.
Second, the difference between rebar and round steel
In construction engineering, round bar and rebar are the popular names for different types of rebar. The differences between them are mainly the following five points:
1. Different shapes. The outer surface of the round steel is smooth; the outer surface of the threaded steel has helical ribs.
2. Different production standards. In the current standard, the round bar refers to HPB235 grade steel bar, and its production standard is "refined hot-rolled smooth steel bar for reinforced concrete" (GB13013); rebar steel generally refers to HRB335 and HRB400 grade steel bars, and its production standard is "reinforced concrete Hot Rolled Ribbed Bar (GB1499).
3. Different strengths. The design strength of the round bar (HPB235) is 210 MPa; the strength of the rebar is higher than that of the round bar, the design strength of the HRB335 is 300 MPa, and the design strength of the HRB400 is 360 MPa.
4. Different types of steel (different chemical composition). Round bar (HPB235) is a carbon steel, steel is Q235; screw steel is a low alloy steel, HRB335 grade steel is 20MnSi (20 manganese silicon); HRB400 grade steel is 20MnSiV or 20MnSiNb or 20MnTi;
5. Physical and mechanical properties are different. Due to the differences in the chemical composition and strength of the steel bars, they differ in physical and mechanical properties. The round steel has better cold bending performance and can be used as a 180-degree hook. The rebar can only be used as a 90-degree straight hook. The round steel has good weldability and can be used with ordinary carbon electrodes. The rebar must be used with low Alloy electrode; Rebar has better toughness and fatigue resistance than round steel.
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