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I. INSPECTION FORCE
rolling may require. 3. One or more checkers, depending upon rapidity of loading. 4. One chemist if check analyses are made in mill laboratory.
II. DUTIES OF INSPECTORS 1. The Chief Rail Inspector shall supervise the inspection force, mill practice, drop tests and make records.
2. One assistant inspector shall follow the mill practice closely, i. e., time of charging, time of tapping, cutting of tests, etc.; record any irregularities, such as too rapid pouring, charging cold ingots, rolling cold bloom, low finishing temperature, behavior of rails under straightening presses or any other departures from good mill practice which may affect the service of the rails.
3. One assistant inspector for night duty shall make drop tests if necessary and follow the mill practice.
4. One or more assistant inspectors shall inspect the rails on the loading beds for surface defects, straightness, etc.
5. One or more checkers shall record the number of rails of each heat accepted and loaded in cach car. A record of the car number and the number of rails of each heat in the car shall be sent to the Division Engineer, the Supervisor, the Roadmaster or other officer to whom the rails are consigned
This prevents the loading of rails rolled from odd ingots, or the loading of more rails than were originally rolled in a heat, or the loading of rails from rejected heats. It also furnishes a check record of the location of the rails if at any time in the future it is desired to remove the rails of a particular heat for any cause whatever.
6. A chemist shall make check analysis of drillings taken from corner of head of the rail, no rails being loaded until the check analysis is finished.
The office to which the rail inspection force reports should keep a record of the history of each heat in a convenient form, so the results obtained from the service of the rails may be traced to the manufacture of the steel or rails.
Rail inspectors should be selected with care and men not familiar with rolling mill practice should not be sent to inspect rails except under the supervision of an experienced rail inspector. As far as possible the inspections should be made by the same men, as they then become familiar with the methods of manufacture peculiar to each mill, for no two mills follow the same procedure even though owned by the same company.
Acceptance of heats meeting the technical requirements of specifications, but in the judgment of the inspector of inferior quality should be deferred pending decision of Engineer of Tests after full report and review of conditions; conversely, rejections of heats whose deficiencies. may be technical only should be similarly governed.
The inspectors cannot be too careful and must exercise good judgment and all possible tact.
Methods of Inspection of Steel Rails For the purpose of gathering information concerning the methods of inspecting rails used by the different railroads, the Chairman of the Sub-Committee sent out a questionnaire to the large railroads asking for information as to their inspection practices. Below are given copies of the letter and the questionnaire sent out, a discussion of the several items, recommendations, and abstracts of the replies received.
LETTER AND QUESTIONNAIRE Letter:
“The Committee on Rail of the American Railway Engineering Association desires to gather information concerning the methods used by the various railroads in the inspection of steel rails. The Committee proposes to study and tabulate the replies and finally submit recommendations as to the methods of rail inspection and organization of inspection staffs. The more full and complete the returns to the questionnaire, the more valuable to the Railroads are the Committee's recommendations apt to be, and you are therefore asked to kindly submit a reply to each of the questions on attached questionnaire, writing and commenting fully on each object.
In case you do not handle the inspection of rails, kindly refer this matter to the officer in charge.” Questionnaire:
1. Describe your inspection organization. 2. Describe the duties of each of the inspectors. 3. Describe selection of samples for chemical analyses, including
ladle test, rail analyses, and check analyses. 4. Describe arrangements for making analyses. 5. Describe selection of samples for drop test or other physical
tests of rails. 6. Describe method and instruments used to determine the deflection
of rails. 7. Describe method and instruments used to determine the elonga
tion of rails. 8. Describe the methods used for the surface inspection of rails. 9. Describe what records are kept of the details of manufacture of
10. Describe method for making sure that there is no error in ship
ping the rails which are tested and inspected, and that no odd ingots from other heats get mixed in with the accepted ones under
the same heat numbers. 11. Other comments and suggestions. 12. Submit a sample of each of the forms used in connection with rail inspection reports.
DISCUSSION Below are given discussions of the several items considered under the general subject of rail inspection. Inspection Organization and Duties of Inspectors.
The organization for inspecting rail and the kinds of inspection made differ on the several railroads. All roads make a final surface inspection to classify the rails into No. 1, No. 2 and rejects, and they also all use the drop test for making physical tests of samples of the rails. Some roads keep a record of all details of manufacture including the making of the steel, giving special attention to irregularities. Others make analyses of the finished rails for the purpose of checking the heat analyses or as an acceptance test. These analyses may be made by the railroad chemists in the mill laboratory or in the railroad laboratory.
In general the inspection organization should consist of the Chief Inspector in charge at the mill, one day and one night drop test inspector, two surface and loading inspectors and such other inspectors and chemists as needed throughout the mill and to make analyses as required by the specifications or the contract. Chemical Analyses.
Most of the railroads accept the heat analyses as delivered to them by the mills. In some cases drillings from the ladle test ingot are sent to the railroad's laboratory and occasional check analyses made for information. Drillings from rails, taken by the inspector, are also sometimes sent to the railroad laboratory for check analyses. Two of the roads send chemists to the mill to make analyses of samples from the rails, using the mill facilities. The analyses of the rails are made to determine the average composition of the steel.
Several years ago the Pennsylvania made a chemical “segregation test" on some of its rails by comparing samples from the corner of the head ("0" or outside position) and the interior of the head ("m" or middle position), requiring the carbon in the m position to not exceed that in the o position by more than a specified amount. A chemical laboratory car with a staff of chemists was sent to the mills to make the analyses.
The heat analysis generally represents fairly closely the average steel as contained in the rails but occasionally the discrepancy is large. and in the case of rails for the more important service, acceptance should probably be based upon the analysis of the finished rails instead of upon the analysis of the heat sample.
Samples for Drop and Other Physical Tests.
Samples for the drop tests are uniformly taken from the second, middle and last full ingot of each heat, from the top end of the rail bar above the A rail. In the case the A rails are rejected, it is permitted to take the sample for further test from the bottom of the A rail in lieu of the top of B rail. To some extent the "nick and break” test on every ingot is used, by noting the fracture of a small piece from the top end of the rail bar. If it shows a defect or “segregation” the A rail of that ingot is rejected. Tensile tests are used somewhat, for information.
Several years ago the Pennsylvania made tests with a "quick bend” tester or hydraulic bending machine. The results were much the same as with the drop test but the hydraulic bender probably has several advantages. A rail is bent either in the drop test machine or hydraulic bender to test the ductility of the part in tension. In the drop machine with either the head or base in tension, some of the breaks are abnormal due to the splitting of the flange, but in the hydraulic bender normal breaks are always obtained by the exhaustion of the tensile ductility. With the hydraulic bender, an automatic load deflection diagram can be obtained. And further a large number of tests could probably be made several times faster in the hydraulic bender than in the drop machine. Deflection,
The usual method of determining the deflection or set of the rail after a blow in the drop machine is to lay a 3-ft. straight edge on the inside of the bend and measure the ordinate from the straight edge to the rail where struck by the tup. The steel scale used generally slides in a slot and is graduated into hundredths, fiftieths, or perhaps tenths of an inch. This direct measurement of the deflection includes also the local indentation of the tup which is a variable amount but averages about .10 inch for the first blow. In order to exclude the local indentation from the measurement, Hunt & Co. uses a gage by which the deflection is measured from the outside of the bend. The gage consists of a bar with two arms at the end of the bar at right angles to it and spaced three feet apart. One form of such a deflection gauge was illustrated in the Proceedings of the American Railway Engineering Association for 1911, Vol. 12, Part 2, page 531. Elongation.
For measuring elongation it is the uniform practice to mark the part to be tested in tension, on the longitudinal center line, with gage marks one inch apart for three inches each side of the center of the specimen. The marking is usually done with a gang of seven prick punches. The elongation is usually measured by means of a flexible steel scale graduated into hundredths of an inch. A more accurate method used somewhat is to gage the elongated space with a pair of fine pointed toolmaker's dividers and then lay this off on the scale.
This method of determining the ductility of the rail is one that was devised by Dr. P. H. Dudley and used by him in 1891 at the plant of the Bethlehem Steel Company, and its adoption marks one of the notable advances in the art of rail inspection.
The practice is divided between testing with the head in tension and with the base in tension. The original method was to test with the base in tension (that is, base down), but the work of the Rail Committee early showed that more information as to the interior condition of the rail is obtained with the head in tension, and its results more nearly correlate with the interior segregation of carbon and phosphorus. The testing with the head down is a better safeguard against failures such as split heads and horizontal fissures, and probably also against transverse fissures, than the testing with the base down, and rails should therefore be tested with the head down. Surface Inspection.
The practice as regards the surface inspection of rails seems to be much the same on all railroads. Its purpose is to classify the rails into No. 1 and No. 2, with an occasional rejection on account of excessive defectiveness of surface. In general the rails are "walked" on four sides, they are examined for straightness, the drilled holes examined for pipes and correctness of drilling, the heat numbers checked and the loading supervised. To some extent the harder or softer rails are kept separate in loading. The Southern Railway has the front ends of all rails milled in order to better detect the presence of pipes. Records of Manufacture.
Most of the roads keep only general records of the details of manufacture or not any. The inspection by Hunt & Co. includes the placing of inspectors to observe and record the details of manufacture beginning with the making of the steel in the open-hearth or bessemer plant, giving especial attention to any irregularities.. Checking Against Errors.
Reliance is generally put upon the mills whose procedure is usually satisfactory, but sometimes count is kept of the ingots poured and the blooms and rails made from each heat. Recommendations.
The inspection procedure will vary somewhat according to the requirements of the specifications and the needs of the road, and in general the inspection methods of most roads are satisfactory. There is one important matter, however, in which the inspection procedure of a number of the roads should be changed; namely, as to the part of the rail which is put in tension in the drop test. As explained under the subject “Elongation," testing the rail with the head down is a better safeguard against obtaining rails subject to failures such as split heads and transverse fissures, and it should therefore be the practice of all roads to test the rails with the head down.