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1. Scope This japenese Industial Standard specifies the carbon steel tubes, hereinafter referred to as the "tubes", used for manufaturing cylinder barrels of pistion type hydraulic cylinders and pneumatic cylinders whose internal surfaces anr furnished by cutting or honing
  Remarks 1.With a previous agreement of the manufacturer, the purchaser may designate the special quality requirements Z 3 specified in Appendix, in addition to those specified in this text.                   
         2. The units and unmerical values given in { } in this Standard are based on the International System of Units (SI) and are appended for informative reference.
Futher, the tradtional units accompanied by numerical values in this Standard shall be converted to the SI units and numerical values on Jan. 1, 1991.

2. Grade and Designation The tubes shall be classified into 7 grades, and their designations shall be as given in Table 1.
                                                       
                                                       Table 1   Designation of Grade
 

* World Standard Comferens Table

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

1017Table 2 Chemical Composition

Renarks 1. When the tube is made of killed steel and also product analysis is required by the purchaser, the tolerances for the values given above shall conform to Table 2 specified in JIS G 0321 for seamless steel tubes and Table 1 for eldctric resistance welded steel tubes.
        2. For the tubes of STC 55, Nb in combination with V may be added. In this case the maximum value of Nb + V shall be 0.15%
 
4. Mechanical Properties The tubes shall be tested in accordance with 8.2 and the resulting tensile strength, yield point or proof stress and elongation shall comply with Table 3.

                                                        Table 3  Mechnical Properties
  

Designation of grade	Tensile strength N/㎟ {kgf/㎟}	Yield point or proof stress N/㎟ {kgf/㎟}	Elongation % No.11 test piece No.12 test piece Longitudinal direction
STC 370	370{38} min.	251{22} min.	30 min.
STC 440	440{45} min.	305{31} min.	10 min.
STC 510 A	510{52} min.	380{39} min.	10 min.
STC 510 B	510{52} min.	380{39} min.	15 min.
STC 540	540{55} min.	390{40} min.	20 min.
STC 590 A	590{60} min.	490{50} min.	10 min.
STC 590 B	590{60} min.	490{50} min.	15 min.

Remarks 1. When the tube under 8mm in thickness is subjected to tensile test by using No.12 test piece, the minimum value of elongation shall be calculated by subtracting 1.5% from the value of elongatin given in Table 3 for each decrese of 1mm and rounding off the result to a whole number according to JIS Z 8401. Examples of calculation are shown in Reference Table 1.
        2. When a tensile test piece is to be taken from the electric resistance steel tube, a No12 test piece shall be taken from a seamless portion
  
5. Dimension, Mass and Dimensional Tolerances

6. Appearance.
  6.1 Both ends of the tube shall be at right anales to the axis of the tube.
  6.2 The inside and outside surfaces of the tube shall be well-finished and free from defects detrimental to practical use.

7. Method of Manufacture

8. Test
 
9. Inspection
  9.1 Inspection The inspection shall be as follows..
    (1) General matters of inspection shall be specified in JIS G 0303.
    (2) The test results of chemical analysis, mechanical properties, dimensions and apperance shall conform to the requirements specified in 3., 4., 5. and 6.
Further, when the special quality requirement given in Appendix are specified by agreement between the purchaser and the manufacturer, the results of inspection shall conform to the requirements specified in Z 3.
    (3) The number of specimens for product analysis shall be agreed upon between the purchaser and the manufacturer.
    (4) The method of sampling specimens for tensile test shall be as follows : Take one specimen from each length of 500m (250m for tubes over 200mm in outside diameter) or its fraction of the tubes of the same dimesions, and then from this specimen take one tensile test piece.
  9.2 Reinspection The tube is entitled to a retest specified in 4.4 in JIS

10.Marking Each tube having passed the inspection shall be marked with the following items. However, in the case of either smaller tubes or a request from the purchaser, the tubes may be bundled together andmarke for each bundle by a suitable means. Ineither case, the order of arranging the item is not specified.
When approved by the purchaser, part of the items may be omitted
(1)Letter symbol of grade
(2)Letter symbol indicating the manufacturing process(¹)
(3)Dimensions(²)
(4)Manufacturer's name or its abbreviation
(5)Letter symbol indicating the special quality requirement, Z
     Note(¹)    The letter symbol indicationg the manufacturing process shall be as follows. However, the dash may be replaced by a bland.
                Hot finished seamless steel tube     :-S-H
                Cole finished seamless steel tube     :-S-C
                Cole finished electric resistance welded steel tube    :-E-C
     Note(²)    The dimensions of the tube shall be expressed by outside (or inside) diameter, wall thickness and length in this order and also in mm. When the outside diameter is specified, the letter symbol "OD", and in the case inside diameter is specified, the letter symbol "ID" shall be placed before the figures that express the outside diameter and inside diameter, respectively.
11. Report The manufacturer shall. as a rule, submit to the purchaser a report of the test results, method of manufacture, ordered dimensions, quantity and work lot number traceable to the history of manufacture, etc.