ASTM A706

ASTM A706 – Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement

Description:

Abstract

This specification covers deformed and plain low-alloy steel bars in cut lengths or coils for concrete reinforcement intended for applications. Restrictive mechanical properties and chemical composition are required for compatibility with controlled tensile property applications or to enhance weldability. The steel shall be electric-furnace, basic-oxygen, or open-hearth processed. Tension test, bend test, and one set of dimensional property tests including bar weight and spacing, height, and gap of deformations shall be made of each bar size rolled from a heat. All tests and inspection shall be made at the place of manufacture prior to shipment, unless otherwise specified, and shall be conducted so as not to interfere unnecessarily with the operation of the works. A retest shall be provided when the specimen fails to meet the strength and elongation property requirements of the specification.

Scope

1.1 General—This specification covers deformed and plain low-alloy steel bars in cut lengths and coils for concrete reinforcement intended for applications where restrictive mechanical properties and chemical composition are required for compatibility with controlled tensile property applications or to enhance weldability. The standard sizes and dimensions of deformed bars and their number designations are given in Table 1.

1.2 Grade—Bars are of three minimum yield strength levels: namely, 60 000 psi [420 MPa], 80 000 psi [550 MPa], and 100 000 psi [690 MPa] designated as Grade 60 [420], Grade 80 [550], and Grade 100 [690], respectively.

1.3 Plain bars, in sizes up to and including 2¹/₂ in. [63.5 mm] in diameter in coils or cut lengths, when ordered, shall be furnished under this specification. For ductility properties (elongation and bending), test provisions of the nearest smaller nominal diameter deformed bar size shall apply. Requirements providing for deformations and marking shall not be applicable.

1.4 Controlled Tensile Properties—This specification limits tensile properties (Table 2) to provide the desired yield/tensile properties for controlled tensile property applications.

1.5 Welding—This specification limits chemical composition (6.2) and carbon equivalent (6.4) to enhance the weldability of the material. When this steel is to be welded, a welding procedure suitable for the chemical composition and intended use or service should be used. The use of the latest edition of AWS D1.4/D1.4M is recommended. The AWS D1.4/D1.4M Welding Code describes the proper selection of the filler metals, preheat/interpass temperatures, as well as, performance and procedure qualification requirements.

NOTE 1: As a result of the 117 000 psi minimum tensile strength for Grade 100 [690], users of this specification should be aware that ACI 318 Type 1 mechanical splice requirements of 125 % of specified yield strength requirements in tension and compression, found in many acceptance criteria, may result in an invalid mechanical splice qualification or verification test when the tensile strength of the bar is between 117 000 psi and 125 000 psi.

1.6 Annex A2 describes the methods for determination of uniform elongation (El_u). Annex A2 is mandatory when Supplementary Requirement S1 is specified by the purchaser (see 4.2.6).

1.7 Requirements for alternate bar sizes are presented in Annex A1. The requirements in Annex A1 only apply when specified by the purchaser (see 4.2.5).

1.8 The text of this specification references notes and footnotes that provide explanatory material. These notes and footnotes, excluding those in tables, shall not be considered as requirements of this specification.

1.9 This specification is applicable for orders in either inch-pound units (Specification A706) or in SI units [Specification A706M].

1.10 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with this specification.