Steel-Tube_JIS G3441 Alloy steel tubes for machine purposes

1. Scope
This Japanese Industrial Standard specifies the alloy steel tubes, hereinfter referred to as the "tubes", used for machinery, automobiles and other machine parts.

2. Grade and Designation
The tubes shall be classified into 7 grades, and their designations shall be as given in Table1

Table 1. Designation of Grade

Designation of grade	Informatibe reference	Classification
Designation of grade	Former symbol	Classification
SCr 420 TK	-	Chromium steel
SCM 415 TK SCM 418 TK SCM 420 TK SCM 430 TK SCM 435 TK SCM 440 TK	- - - Akin to STKS 1 Akin to STKS 3 -	Chromium molybdenum steel

*World Standard Comparative Table*

KS		ASTM		JIS		BS
Number	GRADE	Number	GRADE	Number	GRADE	Number	GRADE
D 3574	SCr 420 TK	A519		G-3441	SCr 420TK	632
	SCM 415 TK				SCM 415TK
	SCM 418 TK				SCM 418TK		CFS10
	SCM 420 TK		5120		SCM 420TK
	SCM 430 TK		4130		SCM 430TK
	SCM 435 TK		4135		SCM 435TK
	SCM 440 TK		4140		SCM 440TK		CFS10
						1717 6323 6323 6323 6323 6323	C6(CF3) CFS, CFS3A CFS4, CFS51 CFS6, CFS7 CFS8, CFS9 CFS11

3. Chemical Composition
The tubes shall be tested in accordance with 7.1 and the ladle analysis values obtained shall conform to Table 2.

Table 2 Chemical Composition

Unit :%

Designation of grade	Former symbol (informative reference)	C	Si	Mn	P	S	Cr	Mo
SCr 420TK SCM 415TK SCM 418TK SCM 420TK SCM 430TK SCM 435TK SCM 440TK	- - - - Akin to STKS 1 Akin to STKS 3 -	0.18~0.23 0.13~0.18 0.16~0.21 0.18~0.23 0.28~0.33 0.33~0.38 0.38~0.43	0.15~0.35 0.15~0.35 0.15~0.35 0.15~0.35 0.15~0.35 0.15~0.35 0.15~0.35	0.60~0.85 0.60~0.85 0.60~0.85 0.60~0.85 0.60~0.85 0.60~0.85 0.60~0.85	0.030 max 0.030 max 0.030 max 0.030 max 0.030 max 0.030 max 0.030 max	0.030 max 0.030 max 0.030 max 0.030 max 0.030 max 0.030 max 0.030 max	0.90~1.20 0.90~1.20 0.90~1.20 0.90~1.20 0.90~1.20 0.90~1.20 0.90~1.20	- 0.15~0.30 0.15~0.30 0.15~0.30 0.15~0.30 0.15~0.30 0.15~0.30

  Remark
1. As impurities, Ni and Cu for each grade shall not exced 0.25 % and 0.30 %, respectively
        2. When the product analysis is required by the purchaser, the tolerances for the values given in the above Table shall be as specified in Table 3 in JIS G 0321


4. Dimensional Tolerances

5. Apperance
  (1) The tube shall be practically straight. and its both ends shall be at right angles to the axis of the tube.
  (2) The tube shall be free from defects detrimental to practical use.
  (3) When particularly required by the purchaser, the surface finishing of tubes shall be agreed upon by the purchaser and the manufacturer.

6. Method of Manufacture
(1) Tubes shall be manufactured by the seamless process or the electric resistance welding process.
  (2) Tube shall, as a rule, be furnished as manufactured, as cold finished, or after annealed. However, the purchaser may specify a heat treatment other than annealing, if necessary.

7. Test
  7.1 Chemical Analysis
   7.1.1 Chemical analysis
The general requirements for chemical analysis and method of sampling specimens for analysis shall be in accordance with the specifications of 3. in JIS G 0303
  7.1.2 Analytical Method
The analytical method shall be in accordance with one of the following Standards.

JIS G 1211, JIS G 1212, JIS G 1213, JIS G 1214, JIS G 1215, JIS G 1216,
JIS G 1217, JIS G 1218, JIS G 1219, JIS G 1253, JIS G 1256, JIS G 1257

8. Inspection
(1)The general requirements for inspection shall be in accordance with JIS G 0303.
  (2) he chemical composition, appearance and dimensions for tube shall conform to the requirements specified in 3., 5.
   (3)The purchaser may specify tensile test (¹), hardness test (²), flattening test, flaring test, grain size test (³)
decarburization test (³) and hydrostatic test, etc, in addition to the inspection items specified in 8.2 In this case, the test items, sampling method, test method and theiracceptance standard shall previously be agreed upon by the manufacturer.
   (4) The number of specimens for product analysis shall be agreed upon by the purchaser and the manufacturer.
         Note
(¹) Tensile test shall be in accordance with JIS Z 2201 and JIS Z 2241.
(²) Hardness test shall be in accordance with JIS Z 2245 .
(³) Grain size test shall be in accordance with JIS G 0551 .
(⁴) Decarburization test shall be in accordance with JIS G 0558

9.Marking
Each tube having passed the inspection shall be legibly marked with the following items.
smaller tubes and other tubes as requested by the purchaser. however, may be bundled and marked for each bundle by suitable means. Whenapproved by the purchaser, part of the items may be omitted.
(1) Designation of grade
(2) Symbol indicating the manufacturing process(⁵)
(3) Dimensions
(4) Manufacturer's name or its abbreviation
         Note (⁵)     The symbols indicating the manufacturing processes shall be as follows..
                     Hot finished seamless steel tube         :-S-H
                     Cold finished seamless steel tube         :-S-C
                     Electric resistance welded steel tubes other than cold finished.:-E-G
                     Cold finished electric resistance welded steel tube   :-E-C

10. Report
The manufacturer shall, as a rule, eubmit to the purchaser reports on the test results, method of manufacture, ordered dimensions, quantity and work lot number traccable to the manufacturing conditions etc.