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46 fied copies of the results of the tests are required, those respecting the testing of Steel tubes and pipes contained in circular 1403, and those regarding boilers for which special certificates are required, re- main in force as heretofore. 11. Standard Test Pieces--The forms and dimensions of test pieces shall be shown in the illustrations. The gage length and the parallel por- tion of the test pieces shall be as shown. The form of the ends to be as required, in order to suit the various methods em- ployed for gripping the test picce. 12. Bending Test.--The specimens sheared from plates, angle bars, and tee bars, for bending tests, shall not be less than 114 in. wide; but for small bars the whole section may be used. The bending specimens of round bars shall be of the full diameter of the bars, as rolled, and the bending tests of forgings and castings shall be made with rectangular test pieces 1 in. wide by 34 in. thick, which shall be machined to size, and have the corners rounded to a radius of 1/16 in.; they shall be bent over their thinner sec- tion. STEEL FOR USE IN BOILERS. 13.. General.--The following instruc- tions refer to steel of ordinary mild qual- ity. Where special or high tensile steel is used, the requirements specified by the Board in each case shall be adhered to. Should any tensile test piece break at a point outside the middle half of its gage length, the test may, at the maker's op- tion and with the surveyor's approval, be discarded, and another test made from the same plate or bar. : PLATES. 14. Number of tests.--A tensile and a bending test shall be taken from each plate, as rolled; but, when the weight of the plate exceeds 214 tons, a tensile and bending test shall be taken from each end. Bending tests only need, however, be made from plates for which a greater stress than is allowed for iron is not wished. The bending tests of plates not intended to be worked in the fire or ex- posed to flame may be made with strips in the same condition as the plates--those from other plates should be made with strips which have been tempered. 15. Preparation of Test Specimens.-- Test specimens may be. cut from the plates, either lengthwise or crosswise, and, whenever practicable, the rolled sur- faces shall be retained on two opposite sides of the test piece. In all cold and temper bend tests of samples 0.5 in. in thickness and above, the rough edge caused by shearing may be removed by filing or grinding; and sam- ples 1 in. in thickness and above may have the edges machined. 16. Temper Bends.--For temper bends the samples should be heated to a blood Tae Marine REVIEW red and quenched in water at a temper- ature not exceeding 80 degs. F. 17. Tensile Strength and Elongation of Plates.--The tensile strength of plates not intended to be worked in the fire or exposed to flame, for which special limits have not been sanctioned, shall be be- tween 27 and 32 tons per sq. in.--that of other plates, from 26 to 30 tons per sq. in. The elongation shall not be less than 20 per cent in a length of 8 in. for material 0.375 in. in thickness and upwards which is required to have a tensile strength of 27 to 32 tons per sq. in., and not less than 23 per cent if the tensile strength is re- quired to be between 26 and 30 tons per sq. in. For material under 0.375 in. in thickness, the elongation may be reduced; but for each eighth of an inch of diminu- tion in thickness, the reduction shall not be more than 3 per cent below the elon- gations named above. 18. Bend Tests.--Bending test pieces shall withstand being bent, without frac- ture, until the sides are parallel at a dis- tance apart of not more than three times the thickness of the specimen. 19. Witnessing of Tests by Surveyor.-- It is very desirable that the surveyor should witness the whole of these tests; but, in the case of plates made from steel manufactured by any of the makers whose names are given in clause 106 of the regulations, he need only select and witness from one in four of the plates of each thickness, unless the weight of the plate is over 2% tons, or special limits of strength, or' in the case of shell plates a minimum tensile strength exceeding 27 tons is required; in which cases the sur- veyor should see the tests made from all the plates. 20. Tensile Strength to be Used in Calculations.--In ascertaining the strength of the shells of cylindrical boilers, the actual minimum tensile strength of the plates, as found by the tests, may, as here- tofore, be used in making the calculations to determine the working pressure. ANGLE, RIVET, AND STAY. BARS. 21. Number of Tests--At least two tensile tests shall be taken from each charge of steel; but when the number of bars, as rolled, from one charge exceeds 15, an additional test shall be made from each further 15 bars or portion thereof. In round bars 134 in. diameter and under, the number given above shall, in each case, be 50 in place of 15. A cold or a temper bend test shall be made from each angle or tee bar rolled, and a cold and a temper bend from every 15 stay bars, as rolled from each charge. No bending tests need be made from rivet bars. 22. Tensile Strength and Elongation: Stays, Angles, and°Tee Bars.--The tensile strength of longitudinal stays, angles, and tee bars shall be between 27 and 32 tons per sq. in. with an elongation of not less than 20 per cent measured on the appro- priate standard test piece--A or B. bor bars for combustion chamber stays, the tensile strength shall be between 26 and 32 tons per sq. in., with an elongation of not less than 23 per cent measured on the standard test piece. But when stay bars are tested on a gage length of four times the diameter--test piece F--the elonga- tions shall be 24 and 28 per cent respec- tively. For tee or angle bars under 0.375 in. in thickness, the elongation may be 3 per cent below that specified for plates. 23. Bend Tests----Bending test pieces of bars shall withstand being bent, with- out fracture, until the sides are parallel at a distance apart of not more than three times the thickness or diameter of the specimen. 24. Rivet Bars.--The tensile strength of rivet bars shall be between 26 and 30 tons per sq. in., with an elongation of not less than 25 per cent,' measured on the standard test piece B, or 30 per cent if measured on test piece F. RIVETS. 25. Nature of Tests--A few rivets of each size shall be selected by the surveyor from the bulk, and shall be subjected to the following tests: (a) The rivet shanks to be bent cold and hammered until the two parts of the shank touch without fracture on the outside of the bend. (0) The rivet heads to be flattened while hot, until their diameter is two and a half times the diameter of the shank, without cracking at the edges. 26. Tensile Tests--A few check ten- sile tests of rivets shall also be made when the surveyor considers it necessary , and, in the case of boilers for which spe- cial certificates are required, a few tensile tests of the rivets of each size shall al- ways, as heretofore, be made in addition to the above. The elongation shall, when practicable, be taken in a length of two and a half times the diameter of the pre- pared part; the tensile strength should be- from 27 fo 32° tons per sq. in; and the contraction of area about 60 per cent. STEEL FORGINGS. 27. General.--The forgings shall be made from sound ingots, and not more than the lowér two-thirds of the ingot may be utilized for forging. The sec- tional area of the body of the forging may not exceed one-fifth of the sectional area of the original ingot; and no part of the forging shall have more than two- thirds of the sectional area of the ingot. All ingot steel forgings shall, after com- pletion, be thoroughly annealed at a uni- form temperature; and, if any subsequent heating is done, the forging shall, if re- quired by the surveyor, be again anneal- ed 28. Number of Tcests.--At least one |