GB Translated English of Chinese Standard: GB NATIONAL STANDARD OF THE

Transcription

1 Translated English of Chinese Standard: GB GB NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA ICS H 44 GB Replacing GB Steel for the Reinforcement of Concrete Part 2: Hot Rolled Ribbed Bars 钢筋混凝土用钢第 2 部分热轧带肋钢筋 (ISO :1991, Steel for the Reinforcement of Concrete Part 2: Ribbed Bars, NEQ) Issued on: August 14, 2008 Implemented on: March 01, 2008 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of the People's Republic of China. Page 1 of 26

2 Table of Contents Foreword Scope Normative references Definitions Types and designations Order content Dimension, shape weight and tolerance Nominal diameter range and recommend diameter Nominal cross-sectional area and theoretical weight Surface shape and dimension tolerance of ribbed bar Length and length tolerance Bend degree and end Weight and weight tolerance Technical requirements Designation and chemical composition Delivery way Mechanical property Processing property Fatigue property Welding property Grain size Surface quality Test Method Inspection items Tensile, bending and reverse bend test Dimension Measurement Measurement of weight tolerance Inspection Rules Characteristic value inspection Delivery inspection Packaging, marking and quality certificate Annex A (Normative) Measuring Method of Steel Bar under General Maximum Force Elongation Annex B (Normative) Inspection Rules of Characteristic Value Annex C (Informative) Calculation Formula of Specific Projected Rib Area of Steel Bar.. 25 No. 1 Modification Sheet to National Standard "Steel for the Reinforcement of Concrete - Part 2: Hot Rolled Ribbed Bars" (GB ) Page 2 of 26

3 Foreword GB 1499 is divided into three parts: Part 1: Hot rolled plain bars; Part 2: Hot rolled ribbed bars; Part 3: Steel bar welting net. This is Part 2 of GB 1499; it corresponds to the international standard ISO :1991 Steel for the Reinforcement of Concrete - Part 2: Ribbed bars ; it is not equivalent to ISO :1991. This part also makes reference to the revision version of international standard "ISO/DIS (2005)". This part replaces GB Hot Rolling Ribbed Steel Bars for the Reinforcement of Concrete. The main changes between this part and GB are as follows: The hot rolled bars of fine grains was added in the scope of application; Add three designations of hot rolled bars of fine grains, namely HRBF335, HRBF400 and HRBF500; Add three definitions general hot-rolled reinforced bar, 3.2 hot rolled bars of fine grains and 3.11 characteristic value; Add Chapter 5 of purchasing content; Add three specifications fatigue property, 7.6 welding performance and 7.7 grain size; Amend "surface quality", "weight deviation measuring" and other provisions; Amend the designation sign of steel bars; HRB335, HRB400 and HRB500 are replaced by 3, 4 and 5 respectively; while HRBF335, HRBF400 and HRBF500 are replaced by C3, C4 and C5; Delete the original Annex B "reference composition of hot-rolled ribbed bars"; Add existing Annex B "test rules of the characteristic value"; Add Annex C "computing formula of relative ribs area of steel bar". Page 3 of 26

4 Steel for the Reinforcement of Concrete Part 2: Hot Rolled Ribbed Bars 1. Scope This part specifies the definition, type, designation, purchasing content, dimension, shape, or weight tolerance, technical specification, testing method, test rules, packing, sign and certificate of quality of the hot rolled ribbed bars of reinforced concrete. This part is applicable to the general hot rolled ribbed bars for the reinforcement of concrete, and hot rolled ribbed bar with ultra-fine grain. This part is not applicable to the recycling steel bar re-rolled by the rolled-steel final product, and remained heat treatment ribbed bars 2. Normative references The provisions in following documents become the provisions of this part of GB 1499, through reference in this Standard. For dated references, the subsequent amendments (excluding corrigendum) or revisions do not apply to this part, however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies. GB/T 222 GB/T Permissible Tolerances for Chemical Composition of Steel Products Methods for Chemical Analysis of Iron, Steel and Alloy - The Reduced Molybdosilicate Spectrophotometric Method for the Determination of Acid-soluble Silicon Content GB/T Methods for Chemical Analysis of Iron, Steel and Alloy - The Ammonium Persulfate Oxidation Volumetric Method for the Determination of Chromium Content GB/T Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Carbonate Separation-diphenyl Carbazide Photometric Method for the Determination of Chromium Content GB/T Methods for Chemical Analysis of Iron, Steel and Alloy - The N-benzoy-N-phenylhydroxylamine Extraction Photometric Method Page 5 of 26

5 , eqv ISO 6892:1998(E)) GB/T 232 GB/T 2101 GB/T 4336 GB/T 6394 GB/T GB/T YB/T 081 YB/T 5126 Metallic Materials - Bend Test (GB/T , eqv ISO 7438:1985(E)) General Requirements of Acceptance, Packaging, Marking, and Certification for Section Steel Standard Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (routine method) Metal Methods for Estimating the Average Grain Size Steel and Steel Products General Technical Delivery Requirements (GB/T , eqv ISO 404:1992) Steel and Iron - Sampling and Preparation of Samples for the Determination of Chemical Composition (GB/T /ISO 14284:1998, IDT) Rule for Rounding off of Numerical Values and Judgment of Testing Values for Technical Standards of Metallurgy Steel Bars for Reinforcement of Concrete-Bend and Rebend Tests (YB/T /ISO , MOD) 3. Definitions The following definitions are applicable to this part. 3.1 Hot rolled bars The steel bar delivered under hot rolling condition; its metallurgical structure is mainly composed of ferrite and pearlite, no other textures (for instance, the β-martensite appeared on the base circle) [Translator Note: Text in red - GB No. 1 Modification Sheet, June 16, 2009 ] are permitted to exist, which may influence the usability of steel bar. 3.2 Hot rolled bars of fine grains The grain refining steel bar formed by applying control rolling and cooling technologies during the hot rolling process; its metallurgical structure is mainly composed of ferrite and pearlite, no other textures (for instance, the β-martensite appeared on the base circle) [Translator Note: Text in red - GB No. 1 Modification Sheet, June 16, 2009 ] are permitted to exist, which may influence the Page 7 of 26

6 usability of steel bar, moreover, the grain size is no thicker than 9-level of the grain size. 3.3 Ribbed bars The steel of which the cross-section is usually round, and the surface is with rib; it is used for concrete structure. 3.4 Longitudinal rib The uniform continuous rib that is parallel to the steel bar axis. 3.5 Transverse rib Those other ribs that are not parallel to the steel bar axis. 3.6 Crescent ribbed bars The steel of which the longitudinal section of transverse rib is crescent and disjoints with longitudinal rib. 3.7 Nominal diameter The diameter of a circle of which the area is equal to the nominal cross-sectional area of the steel bar. 3.8 Specific projected rib area The ratio BETWEEN the projected area of transverse rib on the vertical plane of the steel bar axis AND the product between steel bar nominal perimeter and transverse rib spacing. 3.9 Rib height The distance that is measured from the rib peak to the core surface, which is perpendicular to the steel bar axis Rib spacing The space between two adjacent transverse rib centers, which is parallel to the steel bar axis Characteristic value The percentile value that corresponds to a specified probability, during infinite multiple inspections. Page 8 of 26

7 6.4 Length and length tolerance Length The steel bar shall be delivered in specified lengths, and the delivery length of steel bar shall be described in the contract The steel bar shall be delivered in specified lengths, and the delivery length of steel bar shall be described in contract The steel bar can be delivered by coil, each coil contains one strip of steel bar, and 5% coil amount is allowed to contain two strips of steel bars (insufficient two coils will be regarded as two coils). The coil weight and coil diameter shall be negotiated by the supplier and buyer Length tolerance If the steel bar is delivered in specified length, the length tolerance is ±25mm. If the minimum length is required, then the length tolerance is +50 mm. If the maximum length is required, then the length tolerance is -50 mm. 6.5 Bend degree and end The tortuosity of straight steel bar shall not exert any influence on its general use, while the total tortuosity of steel bar shall not be greater than 0.4% * the total length of steel bar. The steel bar tip shall be sheared completely, so as to ensure that the local deformation won't influence its use. 6.6 Weight and weight tolerance The steel bar can be delivered under the theoretical weight or actual weight condition. If the theoretical weight is applied as delivery condition, then it can be calculated by the steel bar length multiplying the theoretical weight/ meter specified in Table The actual weight and theoretical weight tolerance shall comply with provisions specified in Table 4. Table 4 Nominal diameter/mm Actual weight and theoretical weight tolerance /% 6~12 ±7 14~20 ±5 22~50 ±4 Page 13 of 26

8 Designation HRB335 HRBF335 Table 6 R el /MPa R m /MPa A/% A gt /% Not less than HRB400 HRBF400 HRB500 HRBF The elongation after fracture A of each designation of steel bars with 28mm- 40mm diameter can be reduced by 1%; while the elongation after fracture A of each designation steel bars with diameter of greater than 40mm can be reduced by 2% The applicable designation of steel bar with higher anti-seismic structure requirements is added with E for designations specified in Table 1 (for instance: HRB400E and HRBF400E). These steel bars shall comply with the following clauses of a), b) and c), however, the rest requirements can refer to the same designation steel bar. a) The ratio of actual testing tensile strength to the actual testing yield strength of steel bar R m /R el shall not be less than b) The ratio between actual measuring yield strength and characteristic value for the yield strength of steel bar specified in Table 6 R m /R el shall not be greater than 1.30 c) The general maximum force elongation rate A gt shall not be less than 9%. Note: R m is actual measuring tensile strength of steel bar; while R el is actual measuring yield strength of steel bar As for those steel without sharp yield force, the characteristic value for the yield strength R el shall apply the regulated non-proportionality elongation stress R p The elongation style can be chosen from A or A gt through the mutual negotiation of both the supplier and the purchaser. If the elongation style hasn't been negotiated, then elongation A shall be applied, or elongation A gt shall be applied in arbitration examination. 7.4 Processing property Bending properties According to the provisions in Table 7, the bending surface of steel bar shall not flaw after the bend core diameter bending Page 15 of 26

9 9. Inspection Rules The steel bar inspection can be divided into characteristic value inspection and delivery inspection. 9.1 Characteristic value inspection The characteristic value inspection is applicable to the following conditions: a) Supplier's inspection for the quality control of the products; b) The inspection that is required by the buyer, and negotiated between the supplier and the buyer; c) Product certification and arbitration inspection of the third party The characteristic value inspection shall be carried out according to the rules in Annex B. 9.2 Delivery inspection The delivery inspection is applicable to the inspection of acceptance batch of the steel bar Group-batch rule The steel bar shall be inspected and accepted by batch, while the steel bar batch shall be composed of the steel bars with the same designation, same furnace number and same specification. The usual weight for each batch shall not be bigger than 60t. For more than 60t weight steel bar batch, every 40t increasing (or less than 40t remainder), then one tensile test sample and one bending test sample shall be added It is allowed that the composite batch is composed of different furnace number of the steel bars in the same designation, same smelting process and same pouring procedure; however, the carbon content tolerance among each furnace shall not be bigger than 0.02%, while the manganese content tolerance shall not be bigger than 0.15% Inspection items and sampling quantity The inspection items and sampling quantity of steel bar shall comply with the provisions in Table 8 and clause Inspection result Page 19 of 26

10 Annex B (Normative) Inspection Rules of Characteristic Value B.1 Test batch For the benefit of test, the delivery can be divided into test batch. The batch rules shall comply with the provisions of clause in this part. B.2 Sampling quantity for each batch B.2.1 Chemical composition (check analysis) shall take two samples from different strips of steel bars. B.2.2 All the rest property tests required in this part shall take 15 samples from different steel bars (refers to B.3.1 provisions if 60 samples are applicable). B.3 Assessment of test result B.3.1 Parametric test In order to inspect the required properties, for instance the natural parameter of R el, R m, A gt or A, then the following parameters shall be determined. a) All individual value of Xi in 15 samples (n=15); b) Average m15 (n=15); c) Standard deviation S15 (n=15). If all properties meet the assigned conditions in formula (B.1), then this test batch is qualified. Where: f k Required characteristic value; m S 15 f K... (B.1) 2.33 It is required that coefficient K shall be inspected or accepted, if n=15, confidence level is 90% and defective faction is 5% (P=0.95). If the aforesaid condition can not be met, then the coefficient K' m 15 k shall be S 15 f Page 23 of 26

11 determined by the test result. Where, if K 2, then the test can be continued. In such case, about 45 samples shall be cut off from different strips of steel bars in this test batch, then about 60 test results can be obtained (n=60) totally. If all properties meet the assigned conditions in formula (B.2), then this test batch is qualified. Where: m S 60 >f K (B.2) 1.93 The coefficient K shall be inspected or accepted, under the condition of n=60, confidence level of 90% (1-α=0.90) and defective faction of 5% (P=0.95). B.3.2 Property inspection If the test property is required as the extreme value, and the measuring result of 15 samples comply with the requirement in this part, then this test batch is considered qualified. If there are at-most two test results not meeting the conditions, then the test shall be continued, namely, taking additional 45 samples from different steel bars in the same test batch, then about 60 test results are obtained. If there are maximum 2 of 60 test results not meeting the conditions, then this test batch is considered qualified. B.3.3 Chemical composition Both of the two samples shall comply with the requirements in this part. Page 24 of 26

12 No. 1 Modification Sheet to National Standard "Steel for the Reinforcement of Concrete - Part 2: Hot Rolled Ribbed Bars" (GB ) June 9, Clause 3.1: no other textures are permitted to exist, which may influence the usability of steel bar is change to no other textures (for instance, the β-martensite appeared on the base circle) are permitted to exist, which may influence the usability of steel bar. 2. Clause 3.2: no other textures are permitted to exist, which may influence the usability of steel bar is change to no other textures (for instance, the β-martensite appeared on the base circle) are permitted to exist, which may influence the usability of steel bar. 3. Clause : After HRB335, HRB400 and HRB500 are represented as 3, 4 and 5 respectively; HRBF335, HRBF400 and HRBF500 are represented as C3, C4 and C5 respectively, ADD HRB335E, HRB400E and HRB500E are represented as 3E, 4E and 5E respectively; and HRBF335E, HRBF400E and HRBF500E are represented as C3E, C4E and C5E respectively. END Page 26 of 26