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ASTM A920-14(R2019) pdf free download

ASTM A920-14(R2019) pdf free download.Standard Specification for Steel Bars, Microalloy, Hot-Wrought, Special Quality, Mechanical Properties
1. Scope
1.1 This specification covers hot-wrought, special quality microalloyed carbon steel bars intended for use in applications where as-rolled mechanical properties are desired. A typical end use is hydraulic cylinder shafts. 1.2 The bars shall be furnished to chemical composition and mechanical properties as provided herein. Chemical composi- tion is based on standard carbon steel grades modified to include microalloying elements such as columbium (niobium), vanadium, or molybdenum. Three strength classes are available, designated 75 [520], 80 [550], and 100 [690], corresponding to the minimum yield strength in ksi. 1.3 Sections and sizes of bar steels available are covered in Specification A29/A29M. 1.4 Supplementary Requirements S1 to S5 are provided for use when additional controls or requirements are desired. These shall apply only when specified on the purchase order. 1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 1.6 Unless the order specifies the applicable “M” specifica- tion designation, the material shall be furnished to the inch- pound units. 1.7 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 microalloyed steels, n—carbon steels to which small quantities of certain elements are added in order to enhance mechanical properties. Discussion—This enhancement of mechanical prop- erties results from control of the temperature and cooling rate during the hot-rolling process.
4. Ordering Information
4.1 Orders for material supplied to this specification should include the following, as required, to describe adequately the desired material: 4.1.1 Quantity (weight or number of bars); 4.1.2 Name of material (hot-rolled microalloyed steel bars); 4.1.3 Dimensions; 4.1.4 ASTM specification number and date of issue; 4.1.5 Grade designation or chemical composition limits (see Section 7); 4.1.6 Class; 4.1.7 Additions to the specification and Supplementary Requirements, if required; and, 4.1.8 End use.
7. Chemical Composition
7.1 Typical examples of chemical compositions are shown in Table 1. Other compositions may be specified using one of the following methods: 7.1.1 Base compositions selected from Table 1 of Specifi- cation A576, with the addition of microalloying elements as provided in 7.3 to 7.5, or 7.1.2 Base compositions using the ranges and limits shown in Table 2 of Specification A576, with the addition of microal- loying elements as provided in 7.3 to 7.5. N OTE 1—For improved machinability, alternative sulfur ranges may be specified upon agreement between the purchaser and the producer. Additional machinability-enhancing elements such as lead, bismuth, selenium, or tellurium may also be specified by agreement. 7.2 Silicon analysis shall be 0.15/0.35 %. Silicon content up to 0.80 % maximum may be furnished upon agreement be- tween purchaser and producer. 7.3 Vanadium, columbium (niobium), or molybdenum may be specified singly or in combination, subject to the limits shown in Table 2. The elements and ranges specified shall be upon agreement between the purchaser and the producer. 7.4 Titanium shall be added when specified for refinement of the ferritic-pearlitic (or bainitic) or austenitic grain size. When titanium is specified, the titanium limits shall be as agreed upon between producer and purchaser. The titanium content shall be reported. 7.5 Nitrogen may be specified as a supplement to vanadium, columbium, or titanium. If specified, the nitrogen content shall not exceed 0.030 % and shall be reported. 7.6 Sampling for heat and product analysis shall be in accordance with the requirements of Specification A29/A29M.

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