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1. Scope
  This Japanese Industrial Standard specifies the seamless steel tubes, hereinafter referred to as the "tubes", used for casing tube, core tube and drill rod in drilling
 Remark.
1. The units and numerical values given in { } in this Standard are based on the International System of Unis (SI) and are appended for informative reference.
Further, the treditional units accompanied by numerical values in this Standard shall be converted to the SI units and numerical values on Jan. 1, 1992.

2. Grade and Designation  The tubes shall be classified into 6 grades, and their designations shall be as given in Table 1.
 

	Table 1  Designation of Grade
	New units (For reference) Traditional units Applicatin  STM-C  540  STM-C  640 STM-C  55 STM-C  65 Casing tube, core tube  STM-R  590  STM-R  690  STM-R  780  STM-R  830 STM-R  60 STM-R  70 STM-R  80 STM-R  85 Drill rod

* World Standard Comferens Table

3. Chemical Composition  The tubes shall be tested in accordance with 8.1 and the resulting ladle analysis values shall conform to Table 2.

Table 2  Chemical Composition
	Unit :%

4. Mechanical Properties  The tubes shall be tested in accordance with 8.1 and the resulting tensile strength, yield point or proof stress and elongation shall conform to Table 3-1 or Table 3-2.
 

Table 3   Mechanical Properties

Designation of grade	Tensile strength N/㎟	Yield point or proof stress N/㎟	Elongation %
			No.11 test piece No.12 test piece
STM-C  540	540  min.	-	18  min.
STM-C  640	640  min.	-	16  min.
STM-R  590	590  min.	375  min.	18  min.
STM-R  690	690  min.	440  min.	16  min.
STM-R  780	780  min.	520  min.	15  min.
STM-R  830	830  min.	590  min.	10  min.

5.  Dimensions, Mass and Dimensional Tolerance

6. Appearance The tubes shall be practically straight, and their both ends shall be at right angles to their axes. The tubes shall be free from defects detrimental to practical use.

7. Method of Manufacture 
 (1) Thbes shall be manufactured by seamless process.
 (2) Tubes shall be furnished as cold or hot finished, subject to subsequent adequate heat treatment, if necessary.

8. Test
8.1 Chemical Analysis
8.1.1 Chemical Analysis  General matters of chemical analysis and method of sampling specimens for analysis shall be in accordance with 3. in JIS G 0303.
8.1.2 Analytical Method  The analytical method shall be in accordance with one of the following Standards
      JIS G 1214
      JIS G 1215
JIS G 1253
      JIS G 1256
      JIS G 1257
8.2 Tenile Test
8.2.1 Test Piece The test piece No.11, No.12 A, No.12 B or No.12 C test piece specified in JIS Z 2201, and shall be cut off from the tube along its longitudinal axis.
8.2.2 Test Method The test method shall be as specified in JIS Z 2241

9. Inspection
9.1 Inspection  Inspection shall be as follows 
(1) General matters of inspection shall be as specified in JIS G 0303.
(2) Chemical composition, mechanical 9.1(2) properties, dimensions and appearance for the tubes shall be as specified in 3, 4, 5 and 6
(3) The purchaser may specify a hydrostatic test for drill rod tube in addition to the inspection items specified in (2). In this case, the test pressure and its acciptance criteria shall previously be agreed upon the manufacturer.
The hydrostatic test should, as a rule, be applied to cach tube.
(4) The method of sampling specimens and the number of test pieces for tensile test shall be as follows. Take one test specimen from 100 tubes or its fraction of the same dimensions and the concurrent heat treatment, and then take from this one test piece for the tensile test.
9.2 Reinspection  The tubes are entitled to a retest specified in 4.4 of JIS G 0303 for final acceptance.

10 Making
Each tube having passed the inspection shall be legibly marked with the following items. The order of arranging the items is not specified.
 (1) Designation of grade
 (2) Symbol indicating the manufacturing process(¹)
 (3) Domensions
 (4) Manufacturer's name or its identifying brand
   Note (¹)  The symbol indicating the manufacturing process shall be as follows. The mark-may be replaced by a blank.
                Hot finished seamless steel tube : -S-H
                Cold finished seamless steel tube : -S-C

11. Report
 The manufacturer shall, as a rule, submit to the purchaser a report carrying the test results, methods of manufacture, ordered dimensions, quantity and work lot number traceable to the manufacturing conditons.