Various manufacturer and railroad standard practices call out either "fine grain cast iron per AAR spec" or "gun iron" as the material to be used for locomotive valve cages. We've not yet been able to find anything more helpful for the 1385 project. Any specific leads on the old specs or current equivalent material would be greatly appreciated. mld

edited once for a gross grammatical error...mld

http://s1055.photobucket.com/user/slide ... Gun%20Iron

Bruce E. Babcock

AMERICAN RAILWAY ASSOCIATION
MECHANICAL DIVISION
Master Car Builders Master Mechanics

SPECIFICATIONS
__________
CYLINDERS AND CYLINDER PARTS, CAST IRON
FOR LOCOMOTIVES
Standard
ADOPTED, 1906; REVISED, 1918
_____________

1. Scope. - These specifications cover cast iron for locomotive cylinders, piston valve bushings, piston valve rings and piston head or bull rings.
I. Manufacture
2. Process. – All castings shall be made from good quality, close-grained gray iron. Cylinders shall be cast in dry sand molds.
II. Chemical Properties and Tests.
3. Chemical Composition. – The iron shall conform to the following requirements as to chemical composition:
Phosphorous …………………not over 0.70 per cent.
Sulphur ………………………not over 0.12 per cent.

4. Ladle Analyses. – Analyses shall be made by the manufacturer from a test bar taken during the pouring of each melt, a copy of which shall be given to the purchaser or his representative. This analysis shall conform to the requirements specified in Section 3.

5. Check Analyses. – A check analysis of drillings taken from the fractured end of the transverse test bars may be made by the purchaser, and shall conform to the requirements specified in Section 3.

III. Physical Properties and Tests.
6. Transverse Test. – (a) The arbitration test bar, as described in Section 8, shall be placed horizontally upon supports 12 in. apart center to center, and when tested under a centrally applied load, the transverse strength shall not be less than 3200 lb. for castings 5/8 in. or less in thickness, nor less than 3500 lb. for castings over 5/8 in. in thickness; and the deflection, for either thickness of material, shall not be less than 0.09 in.
(b) If the transverse strength of the deflection of the first test bar does not conform to the requirements specified in paragraph (a), a test may be made on the second bar, as provided for in Section 8, which shall conform to the requirements specified,
(c) The application of the load, for a deflection of 0.10 in., shall be within a period of from 20 to 40 seconds.

7. Chill Test. – A sample of the molten iron shall be chilled in a cast-iron mold. The sample shall be allowed to cool in the mold until it is a dark red or almost black, when it may be knocked out and quenched in water. The sample, when broken, shall show a close-grained gray iron, with a sell defined border of white iron at the bottom of the fracture. The depth of the white iron shall not be less than 1/16 in. for castings 5/8 in. or less in thickness, nor less than 1/8 in. for castings over 5/8 in. in thickness.

8. Test Specimens. – Two arbitration test bars and one chill test bar shall be poured from each melt of iron, in accordance with the form and dimensions as shown in Figs. 1 and 2, provided that the diameter of the arbitration test bar shall not vary more than 0.02 in. above or below the specified size.
9. Number of Tests. – One transverse test, except as specified in Section 6 (b), and one chill test shall be made to represent each melt.
IV. Workmanship.
10. Workmanship. – Castings shall be smooth, well cleaned, free from shrinkage cracks and other injurious defects. When castings are to be machined, sufficient allowance shall be made on patterns that the castings will finish to blue-print dimensions.
V. Marking
11. Marking. – When so specified, the manufacturer’s name or identification mark, the date when cast, the purchaser’s pattern number and such other markings as may be designated, shall be cast on each casting in raised letters and figures.

VI. Inspection and Rejection.
12. Inspection. – (a) The purchaser or his representative shall be given reasonable opportunity to enable him to witness the pouring of the castings and test specimens, as well as to be present when physical tests are made.
(b) In case the inspector is not present to witness the pouring of the castings and test specimens, the manufacturer shall make all tests required by the specifications and, upon request, shall furnish the purchaser with a copy of the results of his tests and shall hold the transverse test and the chill test specimens, subject to examination by the inspector.
(c) The purchaser may make the tests to govern the acceptance or rejection of the material in his own laboratory or elsewhere. Such tests, however, shall be made at the expense of the purchaser.

13. Rejection. – (a) Castings represented by samples which fail to conform to the requirements of these specifications will be rejected.
(b) Individual castings which, subsequent to the above tests and inspection at the foundry or elsewhere and their acceptance, show defects or imperfections will be rejected and shall be replaced by the manufacturer.

14. Rehearing. – Samples tested in accordance with the requirements of these specifications, which represent rejected material, will be held for fourteen days from date of test report.

.

Many Thanks! to all three. This is where RYPN really shines......mld

> I understand that the "G2" sets this material apart from the usual run
> of centrifugal cast grey iron. Perhaps the G stands for "gun".

Since we're providing grading and chemical information, here is some from Dura-Bar on G2 iron:

Specification is similar to ASTM A48 class 40

C 2.60 - 3.75%
Si 1.80 - 3.00
Mn 0.60 - 0.95
S 0.07 max
P 0.12 max

Tensile strength 40,000 psi
Machinability (1212 = 100%) 135%
Hardness (Brinell avg.) 241
Excellent relative wear resistance
Heat-treat response (Rockwell C) 55 - 60

http://www.dura-bar.com/products/g2.cfm


There is also a G2A grade with better surface finish; Ti is used as an inoculant to develop type D graphite (finer grain) in the predominantly pearlitic matrix.

C 2.60 - 3.75%
Si 2.30 - 3.00%
Mn 0.20 - 0.40%
S 0.025% max
P 0.12 max

"Typical expected" tensile strength about 40,000
Hardness (Brinell) 248 min - 311 max

Overmod,
My thanks to you, too for the further details but I'm left with one question. Describing the G2A grade you typed about Ti but in the list of elements typed Si. Which is correct? mld