PROTECTORS FOR THERMO-COUPLES

Thermo-couples must be protected from the danger of mechanical injury. For this purpose tubes of various refractory materials are made to act as protectors. These in turn are usually protected by outside metal tubes. Pure wrought iron is largely used for this purpose as it scales and oxidizes very slowly. These tubes are usually made from 2 to 4 in. shorter than the inner tubes. In lead baths the iron tubes often have one end welded closed and are used in connection with an angle form of mounting.

FIG. 133.—Bent handle thermocouple with protector.

Where it is necessary for protecting tubes to project a considerable distance into the furnace a tube made of nichrome is frequently used. This is a comparatively new alloy which stands high temperatures without bending. It is more costly than iron but also much more durable.

When used in portable work and for high temperatures, pure nickel tubes are sometimes used. There is also a special metal tube made for use in cyanide. This metal withstands the intense penetrating characteristics of cyanide. It lasts from six to ten months as against a few days for the iron tube.

The inner tubes of refractory materials, also vary according to the purposes for which they are to be used. They are as follows:

Marquardt mass tubes for temperatures up to 3,000°F., but they will not stand sudden changes in temperature, such as in contact with intermittent flames, without an extra outer covering of chamotte, fireclay or carborundum.

FIG. 134.—Other styles of bent mounting.

Fused silica tubes for continuous temperatures up to 1,800°F. and intermittently up to 2,400°F. The expansion at various temperatures is very small, which makes them of value for portable work. They also resist most acids.

Chamotte tubes are useful up to 2,800°F. and are mechanically strong. They have a small expansion and resist temperature changes well, which makes them good as outside protectors for more fragile tubes. They cannot be used in molten metals, or baths of any kind nor in gases of an alkaline nature. They are used mainly to protect a Marquardt mass or silica tube.

Carborundum tubes are also used as outside protection to other tubes. They stand sudden changes of temperature well and resist all gases except chlorine, above 1,750°F. Especially useful in protecting other tubes against molten aluminum, brass, copper and similar metals.

Clay tubes are sometimes used in large annealing furnaces where they are cemented into place, forming a sort of well for the insertion of the thermo-couple. They are also used with portable thermo-couples for obtaining the temperatures of molten iron and steel in ladles. Used in this way they are naturally short-lived, but seem the best for this purpose.

FIG. 135.—Straight thermocouple and guard.

Corundite tubes are used as an outer protection for both the Marquardt mass and the silica tubes for kilns and for glass furnaces. Graphite tubes are also used in some cases for outer protections.

Calorized tubes are wrought-iron pipe treated with aluminum vapor which often doubles or even triples the life of the tube at high temperature.

These tubes come in different sizes and lengths depending on the uses for which they are intended. Heavy protecting outer tubes may be only 1 in. in inside diameter and as much as 3 in. outside diameter, while the inner tubes, such as the Marquardt mass and silica tubes are usually about ¾ in. outside and 3/8 in. inside diameter. The length varies from 12 to 48 in. in most cases.

Special terminal heads are provided, with brass binding posts for electrical connections, and with provisions for water cooling when necessary.

APPENDIX

TABLE 32.—Temperature Conversion Tables.

TABLE 33.—Comparison Between Degrees Centigrade and Degrees Fahrenheit.

TABLE 34.—Weight of Round, Octagon and Square Carbon Tool Steel per Foot.

TABLE 35.—Weight of Round Carbon Tool Steel 12 In. in Diameter and Larger, per Foot.

TABLE 36.—Decimal Equivalents of a foot.

TEMPERATURE CONVERSION TABLES

By ALBERT SAUVEUR

-459.4 to 0			0 to 100						100 to 1000
C.		F.	C.		F.	C.		F.	C.		F.	C.		F.
-273	-459.4		-17.8	0	32	10.0	50	122.0	38	100	212	260	500	932
-268	-450		-17.2	1	33.8	10.6	51	123.8	43	110	230	266	510	950
-262	-440		-16.7	2	35.6	11.1	52	125.6	49	120	248	271	520	968
-257	-430		-16.1	3	37.4	11.7	53	127.4	54	130	266	277	530	986
-251	-420		-15.6	4	39.2	12.2	54	129.2	60	140	284	282	540	1004
-246	-410		-15.0	5	41.0	12.8	55	131.0	66	150	302	288	550	1022
-240	-400		-14.4	6	42.8	13.3	56	132.8	71	160	320	293	560	1040
-234	-390		-13.9	7	44.6	13.9	57	134.6	77	170	336	299	570	1058
-229	-380		-13.3	8	46.4	14.4	58	136.4	82	180	358	304	580	1076
-223	-370		-12.8	9	48.2	15.0	59	138.2	88	190	374	310	590	1094
-218	-360		-12.2	10	50.0	15.6	60	140.0	93	200	392	316	600	1112
-212	-350		-11.7	11	51.8	16.1	61	141.8	99	210	410	321	610	1130
-207	-340		-11.1	12	53.6	16.7	62	143.6	100	212	413	327	620	1148
-201	-330		-10.6	13	55.4	17.2	63	145.4	104	220	428	332	630	1166
-196	-320		-10.0	14	57.2	17.8	64	147.2	110	230	446	338	640	1184
-190	-310		-9.44	15	59.0	18.3	65	149.0	116	240	464	343	650	1202
-184	-300		-8.89	16	61.8	18.9	66	150.8	121	250	482	349	660	1220
-179	-290		-8.33	17	63.6	19.4	67	152.6	127	260	500	354	670	1238
-173	-280		-7.78	18	65.4	20.0	68	154.4	132	270	518	360	680	1256
-169	-273	-459.4	-7.22	19	67.2	20.6	69	156.2	138	280	536	366	690	1274
-168	-270	-454	-6.67	20	68.0	21.1	70	158.0	143	290	554	371	700	1292
-162	-260	-436	-6.11	21	69.8	21.7	71	159.8	149	300	572	377	710	1310
-157	-250	-418	-5.56	22	71.6	22.2	72	161.6	154	310	590	382	720	1328
-151	-240	-400	-5.00	23	73.4	22.8	73	163.4	160	320	608	388	730	1346
-146	-230	-382	-4.44	24	75.2	23.3	74	165.2	166	330	626	393	740	1364
-140	-220	-364	-3.89	25	77.0	23.9	75	167.0	171	340	644	399	750	1382
-134	-210	-346	-3.33	26	78.8	24.4	76	168.8	177	350	662	404	760	1400
-129	-200	-328	-2.78	27	80.6	25.0	77	170.6	182	360	680	410	770	1418
-123	-190	-310	-2.22	28	82.4	25.6	78	172.4	188	370	698	416	780	1436
-118	-180	-292	-1.67	29	84.2	26.1	79	174.2	193	380	716	421	790	1454
-112	-170	-274	-1.11	30	86.0	26.7	80	176.0	199	390	734	427	800	1472
-107	-160	-256	-0.56	31	87.8	27.2	81	177.8	204	400	752	432	810	1490
-101	-150	-238	0	32	89.6	27.8	82	179.6	210	410	770	438	820	1508
-95.6	-140	-220	0.56	33	91.4	28.3	83	181.4	216	420	788	443	830	1526
-90.0	-130	-202	1.11	34	93.2	28.9	84	183.2	221	430	806	449	840	1544
-84.4	-120	-184	1.67	35	95.0	29.4	85	185.0	227	440	824	454	850	1562
-78.9	-110	-166	2.22	36	96.8	30.0	86	186.8	232	450	842	460	860	1580
-73.3	-100	-148	2.78	37	98.6	30.6	87	188.6	238	460	860	466	870	1598
-67.8	-90	-130	3.33	38	100.4	31.1	88	190.4	243	470	878	471	880	1616
-62.2	-80	-112	3.89	39	102.2	31.7	89	192.2	249	480	896	477	890	1634
-56.7	-70	-94	4.44	40	104.0	32.2	90	194.0	254	490	914	482	900	1652
-51.1	-60	-76	5.00	41	105.8	32.8	91	195.8				488	910	1670
-45.6	-50	-58	5.56	42	107.6	33.3	92	197.6				493	920	1688
-40.0	-40	-40	6.11	43	109.4	33.9	93	199.4				499	930	1706
-34.4	-30	-22	6.67	44	111.2	34.4	94	201.2				504	940	1724
-28.9	-20	4	7.22	45	113.0	35.0	95	203.0				510	950	1742
-23.3	-10	14	7.78	46	114.8	35.6	96	204.8				516	960	1760
-17.8	0	32	8.33	47	116.6	36.1	97	206.6				521	970	1778
			8.89	48	118.4	36.7	98	208.4				527	980	1796
			9.44	49	120.2	37.2	99	210.2				532	990	1814
						37.8	100	212.0				538	1000	1832

1000 to 2000						2000 to 3000
C.		F.	C.		F.	C.		F.	C.		F.
538	1000	1832	816	1500	2732	1093	2000	3632	1371	2500	4534
543	1010	1850	821	1510	2750	1099	2010	3650	1377	2510	4552
549	1020	1868	827	1520	2768	1104	2020	3668	1382	2520	4560
554	1030	1886	832	1530	2786	1110	2030	3686	1388	2530	4588
560	1040	1904	838	1540	2804	1116	2040	3704	1393	2540	4606
566	1050	1922	843	1550	2822	1121	2050	3722	1399	2550	4622
571	1060	1940	849	1560	2840	1127	2060	3740	1404	2560	4640
577	1070	1958	854	1570	2858	1132	2070	3758	1410	2570	4658
582	1080	1976	860	1580	2876	1138	2080	3776	1416	2580	4676
588	1090	1994	866	1590	2894	1143	2090	3794	1421	2590	4694
593	1100	2012	871	1600	2912	1149	2100	3812	1427	2600	4712
599	1110	2030	877	1610	2930	1154	2110	3830	1432	2610	4730
604	1120	2048	882	1620	2948	1160	2120	3848	1438	2620	4748
610	1130	2066	888	1630	2966	1166	2130	3866	1443	2630	4766
616	1140	2084	893	1640	2984	1171	2140	3884	1449	2640	4784
621	1150	2102	899	1650	3002	1777	2150	3902	1454	2650	4802
627	1160	2120	904	1660	3020	1182	2160	3920	1460	2660	4820
632	1170	2138	910	1670	3038	1188	2170	3938	1466	2670	4838
638	1180	2156	916	1680	3056	1193	2180	3956	1471	2680	4854
643	1190	2174	921	1690	3074	1199	2190	3974	1477	2690	4876
649	1200	2192	927	1700	3092	1204	2200	3992	1482	2700	4892
654	1210	2210	932	1710	3110	1210	2210	4010	1488	2710	4910
660	1220	2228	938	1720	3128	1216	2220	4028	1493	2720	4928
666	1230	2246	943	1730	3146	1221	2230	4046	1499	2730	4946
671	1240	2264	949	1740	3164	1227	2240	4064	1504	2740	4964
677	1250	2282	954	1750	3182	1232	2250	4082	1510	2750	4982
682	1260	2300	960	1760	3200	1238	2260	4100	1516	2760	5000
688	1270	2318	966	1770	3218	1243	2270	4118	1521	2770	5018
693	1280	2336	971	1780	3236	1249	2280	4136	1527	2780	5036
699	1290	2354	977	1790	3254	1254	2290	4154	1532	2790	5054
704	1300	2372	982	1800	3272	1260	2300	4172	1538	2800	5072
710	1310	2390	988	1810	3290	1266	2310	4190	1543	2810	5090
716	1320	2408	993	1820	3308	1271	2320	4208	1549	2820	5108
721	1330	2426	999	1830	3326	1277	2330	4226	1554	2830	5126
727	1340	2444	1004	1840	3344	1282	2340	4244	1560	2840	5144
732	1350	2462	1010	1850	3362	1288	2350	4262	1566	2850	5162
738	1360	2480	1016	1860	3380	1293	2360	4280	1571	2860	5180
743	1370	2498	1021	1870	3398	1299	2370	4298	1577	2870	5198
749	1380	2516	1027	1880	3416	1304	2380	4316	1582	2880	5216
754	1390	2534	1032	1890	3434	1310	2390	4334	1588	2890	5234
760	1400	2552	1038	1900	3452	1316	2400	4352	1593	2900	5252
766	1410	2570	1043	1910	3470	1321	2410	4370	1599	2910	5270
771	1420	2588	1049	1920	3488	1327	2420	4388	1604	2920	5288
777	1430	2606	1054	1930	3506	1332	2430	4406	1610	2930	5306
782	1440	2624	1060	1940	3524	1338	2440	4424	1616	2940	5324
788	1450	2642	1066	1950	3542	1343	2450	4442	1621	2950	5342
793	1460	2660	1071	1960	3560	1349	2460	4460	1627	2960	5360
799	1470	2678	1077	1970	3578	1354	2470	4478	1632	2970	5378
804	1480	2696	1082	1980	3596	1360	2480	4496	1638	2980	5396
810	1490	2714	1088	1990	3614	1366	2490	4514	1643	2990	5414
			1093	2000	3632				1649	3000	5432

C.		F.	C.		F.
0.56	1	1.8	3.33	6	10.8
1.11	2	3.6	3.89	7	12.6
1.67	3	5.4	4.44	8	14.4
2.22	4	7.2	5.00	9	16.2
2.78	5	9.0	5.56	10	18.0

NOTE.—The numbers in bold face type refer to the temperature either in degrees Centigrade or Fahrenheit which it is desired to convert into the other scale. If converting from Fahrenheit degrees to Centigrade degrees the equivalent temperature will be found in the left column, while if converting from degrees Centigrade to degrees Fahrenheit, the answer will be found in the column on the right. These tables are a revision of those by Sauveur & Boylston, metallurgical engineers, Cambridge, Mass. Copyright, 1920.

Those using pyrometers will find this and the preceding conversion table of great convenience:

TABLE 33.—COMPARISON BETWEEN DEGREES CENTIGRADE AND DEGREES FAHRENHEIT
Degrees		Degrees		Degrees		Degrees		Degrees		Degrees		Degrees
F.	C.	F.	C.	F.	C.	F.	C.	F.	C.	F.	C.	F.	C.
-40	-40.0	3	-16.1	46	7.7	89	31.6	132	55.5	175	79.4	275	135.0
-39	-39.4	4	-15.5	47	8.3	90	32.2	133	56.1	176	80.0	300	148.8
-38	-38.8	5	-15.0	48	8.8	91	32.7	134	56.6	177	80.5	325	162.7
-37	-38.3	6	-14.4	49	9.3	92	33.3	135	57.2	178	81.1	350	176.6
-36	-37.7	7	-13.8	50	10.0	93	33.9	136	57.7	179	81.6	375	190.5
-35	-37.2	8	-13.3	51	10.5	94	34.4	137	58.3	180	82.2	400	204.4
-34	-36.6	9	-12.7	52	11.1	95	35.0	138	58.8	181	82.7	425	218.3
-33	-36.1	10	-12.2	53	11.6	96	35.5	139	59.4	182	83.3	450	232.2
-32	-35.5	11	-11.6	54	12.2	97	36.1	140	60.0	183	83.8	475	246.1
-31	-35.0	12	-11.1	55	12.7	98	36.6	141	60.5	184	84.4	500	260.0
-30	-34.4	13	-10.5	56	13.3	99	37.2	142	61.1	185	85.0	525	273.8
-29	-33.9	14	-10.0	57	13.8	100	37.7	143	61.6	186	85.5	550	287.7
-28	-33.3	15	-9.3	58	14.4	101	38.3	144	62.2	187	86.1	575	301.6
-27	-32.7	16	-8.8	59	15.0	102	38.8	145	62.7	188	86.6	600	315.5
-26	-32.2	17	-8.3	60	15.5	103	39.4	146	63.3	189	87.2	625	329.4
-25	-31.6	18	-7.7	61	16.1	104	40.0	147	63.8	190	87.7	650	343.3
-24	-31.1	19	-7.2	62	16.6	105	40.5	148	64.4	191	88.3	675	357.2
-23	-30.5	20	-6.6	63	17.2	106	41.1	149	65.0	192	88.8	700	371.1
-22	-30.0	21	-6.1	64	17.7	107	41.6	150	65.5	193	89.4	725	385.0
-21	-29.4	22	-5.5	65	18.3	108	42.2	151	66.1	194	90.0	750	398.8
-20	-28.8	23	-5.0	66	18.8	109	42.7	152	66.6	195	90.5	775	412.7
-19	-28.3	24	-4.4	67	19.4	110	43.3	153	67.2	196	91.1	800	426.6
-18	-27.7	25	-3.8	68	20.0	111	43.8	154	67.7	197	91.6	825	440.5
-17	-27.2	26	-3.3	69	20.5	112	44.4	155	68.3	198	92.2	850	454.4
-16	-26.6	27	-2.7	70	21.1	113	45.0	156	68.8	199	92.7	875	468.3
-15	-26.1	28	-2.2	71	21.6	114	45.5	157	69.4	200	93.3	900	482.2
-14	-25.5	29	-1.6	72	22.2	115	46.1	158	70.0	201	93.8	925	496.1
-13	-25.0	30	-1.1	73	22.7	116	46.6	159	70.5	202	94.4	950	510.0
-12	-24.4	31	-0.5	74	23.3	117	47.2	160	71.1	203	95.0	975	523.8
-11	-23.8	32	-0.0	75	23.8	118	47.7	161	71.6	204	95.5	1,000	537.7
-10	-23.3	33	+0.5	76	24.4	119	48.3	162	72.2	205	96.1	1,100	593.3
-9	-22.7	34	1.1	77	25.0	120	48.8	163	72.7	206	96.6	1,200	648.8
-8	-22.2	35	1.6	78	25.5	121	49.4	164	73.3	207	97.2	1,300	704.4
-7	-21.6	36	2.2	79	26.1	122	50.0	165	73.8	208	97.7	1,400	760.0
-6	-21.1	37	2.7	80	26.6	123	50.5	166	74.4	209	98.3	1,500	815.5
-5	-20.5	38	3.3	81	27.2	124	51.1	167	75.0	210	98.8	1,600	871.1
-4	-20.0	39	3.8	82	27.7	125	51.6	168	75.5	211	99.4	1,700	926.6
-3	-19.4	40	4.4	83	28.3	126	52.2	169	76.1	212	100.0	1,800	982.2
-2	-18.8	41	5.0	84	28.8	127	52.7	170	76.6	213	100.5	1,900	1,037.7
-1	-18.3	42	5.5	85	29.4	128	53.3	171	77.2	214	101.1	2,000	1,093.3
0	-17.7	43	6.1	86	30.0	129	53.8	172	77.7	215	101.6	2,100	1,148.8
+1	-17.2	44	6.6	87	30.5	130	54.4	173	78.3	225	107.2	2,200	1,204.4
2	-16.6	45	7.2	88	31.1	131	55.0	174	78.8	250	121.1	2,300	1,260.0

Degrees Fahrenheit =	9 x degrees C.	+ 32
	5
Degrees Centigrade =	5 x (degrees F. - 32)
	9

Three other useful tables are also given on the following pages.

Size in inches	Round	Octagon	Square	Size in inches	Round	Octagon	Square
1/16	0.010	0.011	0.013	2-1/2	16.79	17.71	21.37
1/8	0.042	0.044	0.053	2-5/8	18.51	19.52	23.56
3/16	0.094	0.099	0.120	2-3/4	20.31	21.42	25.86
1/4	0.168	0.177	0.214	2-7/8	22.20	23.41	28.27
5/16	0.262	0.277	0.334	3	24.17	25.50	30.78
3/8	0.378	0.398	0.481	3-1/8	26.23	27.66	33.40
7/16	0.514	0.542	0.655	3-1/4	28.37	29.92	36.12
1/2	0.671	0.708	0.855	3-3/8	30.59	32.27	38.95
9/16	0.850	0.896	1.082	3-1/2	32.90	34.70	41.89
5/8	1.049	1.107	1.336	3-5/8	35.29	37.23	44.94
11/16	1.270	1.339	1.616	3-3/4	37.77	39.84	48.09
3/4	1.511	1.594	1.924	3-7/8	40.33	42.54	51.35
13/16	1.773	1.870	2.258	4	42.97	45.34	54.72
7/8	2.056	2.169	2.618	4-1/4	48.51	51.17	61.77
15/16	2.361	2.490	3.006	4-1/2	54.39	57.37	69.25
1	2.686	2.833	3.420	4-3/4	60.60	63.92	77.16
1-1/8	3.399	3.585	4.328	5	67.15	70.83	85.50
1-1/4	4.197	4.427	5.344	5-1/4	74.03	78.08	94.26
1-3/8	5.078	5.356	6.646	5-1/2	81.25	85.70	103.45
1-1/2	6.044	6.374	7.695	5-3/4	88.80	93.67	113.07
1-5/8	7.093	7.481	9.031	6	96.69	101.99	123.12
1-3/4	8.226	8.674	10.474	7	131.61	138.82	167.58
1-7/8	9.443	9.960	12.023	8	171.90	181.32	218.88
2	10.744	11.332	13.680	9	217.57	229.48	277.02
2-1/8	12.129	12.793	15.443	10	268.60	283.31	342.00
2-1/4	13.598	14.343	17.314	11	325.01	342.80	413.82
2-3/8	15.151	15.981	19.291	12	386.79	407.97	492.48

High-speed steel, being more dense than carbon steel, weighs from 10 to 11 per cent more than carbon steel. This should be added to figures given in the table.

Diameter, inches	Weight per foot	Diameter, inches	Weight per foot	Diameter, inches	Weight per foot
12	386.790	15-7/8	677.527	19-3/4	1,049.010
12-1/8	395.518	16	687.600	19-7/8	1,061.705
12-1/4	404.246	16-1/8	699.017	20	1,074.400
12-3/8	412.974	16-1/4	710.435	20-1/8	1,088.502
12-1/2	421.702	16-3/8	721.852	20-1/4	1,102.605
12-5/8	430.430	16-1/2	733.270	20-3/8	1,116.707
12-3/4	439.158	16-5/8	744.687	20-1/2	1,130.810
12-7/8	447.886	16-3/4	756.105	20-5/8	1,144.912
13	456.615	16-7/8	767.522	20-3/4	1,159.015
13-1/8	465.343	17	778.940	20-7/8	1,173.118
13-1/4	474.071	17-1/8	790.358	21	1,187.220
13-3/8	482.799	17-1/4	801.777	21-1/8	1,201.322
13-1/2	491.527	17-3/8	813.195	21-1/4	1,215.425
13-5/8	500.255	17-1/2	824.614	21-3/8	1,229.527
13-3/4	508.983	17-5/8	836.030	21-1/2	1,243.630
13-7/8	517.711	17-3/4	847.447	21-5/8	1,257.732
14	526.440	17-7/8	858.863	21-3/4	1,271.835
14-1/8	536.512	18	870.280	21-7/8	1,285.937
14-1/4	546.585	18-1/8	883.105	22	1,300.040
14-3/8	556.657	18-1/4	895.920	22-1/8	1,315.485
14-1/2	566.730	18-3/8	908.740	22-1/4	1,330.930
14-5/8	576.802	18-1/2	921.560	22-3/8	1,346.375
14-3/4	586.875	18-5/8	934.380	22-1/2	1,361.820
14-7/8	596.947	18-3/4	947.200	22-5/8	1,377.265
15	607.020	18-7/8	960.020	22-3/4	1,392.710
15-1/8	617.092	19	972.840	22-7/8	1,408.155
15-1/4	627.165	19-1/8	985.035	23	1,423.600
15-3/8	637.237	19-1/4	998.230	23-1/8	1,454.490
15-1/2	647.310	19-3/8	1,010.925	23-1/4	1,485.380
15-5/8	657.382	19-1/2	1,023.620	23-3/8	1,516.270
15-3/4	667.455	19-5/8	1,036.315	24	1,547.160

To find the weight of discs made of carbon steel, in diameters up to and including 12 in., without any allowance for finishing multiply the per foot weight of round bar steel, shown herewith by the decimal equivalent of a foot given in the following table:

In.	0	1/8	1/4	3/8	1/2	5/8	3/4	7/8
0	0.000	0.010	0.021	0.031	0.042	0.052	0.063	0.073
1	0.083	0.094	0.104	0.115	0.125	0.135	0.146	0.156
2	0.167	0.177	0.188	0.198	0.208	0.219	0.229	0.240
3	0.250	0.260	0.270	0.281	0.292	0.302	0.313	0.323
4	0.333	0.344	0.354	0.364	0.375	0.385	0.396	0.406
5	0.416	0.427	0.437	0.448	0.458	0.469	0.479	0.480
6	0.500	0.510	0.520	0.531	0.542	0.552	0.563	0.573
7	0.583	0.594	0.604	0.615	0.625	0.635	0.646	0.656
8	0.666	0.677	0.687	0.698	0.708	0.719	0.729	0.740
9	0.750	0.760	0.770	0.781	0.792	0.802	0.813	0.823
10	0.833	0.844	0.854	0.865	0.875	0.885	0.896	0.906
11	0.916	0.927	0.937	0.948	0.953	0.969	0.979	0.990

EXAMPLE.—If the weight of a carbon steel disc 7 in. diameter, 1-5/8 in. thick is desired, turn to page 233, where the per foot weight of 7 in. round is given as 131.6 lb. Multiply this by the decimal equivalent of 1-5/8 in., or 0.135, as shown in the above table, and the product will be the net weight of the disc.

131.61	lb.	= the weight of 1 ft. of 7 in. round.
0.135		= the per foot decimal equivalent of 1-5/8 in:
65805
39483
13161
17.76735	lb.	= weight of disc 7 in. diam. 1-5/8 in. thick without any allowance for finishing.

AUTHORITES QUOTED

ADDIS, W H., [102]
AMERICAN MACHINISTS' HANDBOOK, [69]
AMERICAN STEEL TREARERS' SOCIETY, [119]
AMERICAN GEAR MFRS. ASSO., [115]
AUTOMATIC AND ELECTRIC FURNACES LTD., [161]
ARNOLD, PROF. J. O., [167]

BURLEIGH, R. W.
BORDEN, B.
BOKER, HERMAN & Co.
BROWN INSTRUMENT Co., [224]
BROWN-LIPE-CHAPLIN Co., [121]

CAMPBELL, H. H.
CARHART, H. A., [42]
CLAYTON, C. Y., [112]
CURTIS AIRPLANE Co.

ENGLEHARD, CHARLES, [227]
ENSAW, HOWARD, [79], [95]

FIRTH-STERLING STEEL Co., [176]
FIRTH, THOMAS & SONS, [137]
FOWLER, HENRY, [151]

GILBERT & BARKER, [164], [188]

HAYWAHD, C. R., [35]
HOWE, DR. H. M., [8], [108]
HOOVER STEEL BALL CO., [61]
HEATHCOTE, H. L., [85]
HARRIS, MATTHEW, [94]
HUNTER, J. V., [192]

JANITZKY, E. J., [119]
JOHNSTON, A. B., [35]
JUTHE, K. A., [1], [24], [65], [75], [79], [105], [145]

LATROBE STEEL CO., [150], [178]
LUDLUM STEEL CO., [175]
LEEDS & NORTHRUP CO., [211]
LYMAN, W. H., [199]

MANSFIELD, C. A.
MIDVALE STEEL Co.
McKENNA, ROY C., [164]
MOULTON, SETH A., [199]

NILES, BEMENT, POND, [67]

PARKER, S. W.
POOLE, C. R.

RAWDON, H. S., [110], [113]

S. A. E. (SOCIETY AUTOMOTIVE ENGINEERS), [39], [46], [49], [134]
SAUVEUR, ALBERT, [105], [232]
SPRINGFIELD ARMORY, [78]
SELLACK, T. G.
SMITH, A. J., [101]
SHIRLEY, ALFRED J.

TAYLOR INSTRUMENT Co., [215]
THUM, E. E., [12-23]; [105-121].
TIEMANN, H. P., [11]

U. S. BALL BEARING Co.
UNITED STEEL Co.
UNDERWOOD, CHARLES N.

VAN DE VENTER, JOHN H., [86]

WALP, H. O., [109]
WOOD, HAROLD F., [46]
WHEELOCK, LOVEJOY & Co., [69]

INDEX

ABC of iron and steel, [ix]
Absorption of carbon, rate of, [83]
Air hardening steels, [183]
Analysis of high speed steel, [165]
Allotropic modifications, [107]
Alloy steel, annealing, [76]
properties of, [34]
Alloys and their effect, [16], [24]
in high speed steel, [166]
in steel, value of, [16], [24]
upon steel, [24]
Alpha iron, [106]
Annealing, [113], [115]
care in, [154], [155]
furnace, [190]
high-chromium steel, [36]
high speed tools, [174]
in bone, [77]
methods, [122]
proper, [117]
rifle components, [78]
rust-proof steel, [36]
steels, [75]
temperature, [119]
Arrests, [106]
Austentite, [108], [111]
Automotive industry, application of Liberty engine materials to, [46]
temperature control, [225]
Axles, heat treatment of, [61]

Balls, making steel, [61]
Barium chloride process, [178]
Baths for tempering, [157]
Bessemer converter, [2]
Beta iron, [106]
Blending compounds, [103]
Blister steel, [81]
Blue brittleness, [56]
Bone, annealing in, [77]
Boxes for case hardening or carburizing, [80]
Breaking test gears, [126]
Brinell hardness, [22]
Broach hardening furnace, [188]
Brown automatic pyrometer, [224]
Burning, [65]

Calorized tubes, [229]
Carbon, [13]
content at various temperatures, [84]
content of case hardened work, [81]
in cast iron, [ix]
in tool steel, [149-150]
introduction of, [96]
penetration of, [95]
steel, [11]
steel forgings, Liberty engine, [48]
steel tools, [145]
steels, S. A. E., 10, [39]
steels, temper colors, [163]
strengthens iron, [13]
tool steel, forging, [65]
Carbonizing, see Carburizing
Carborundum tubes, [229]
Carburization, preventing, [93]
Carburizing by gas, [88], [93]
boxes, [80]
compounds, [88], [102]
gas consumption by, [101]
local, [94]
material, [85]
nickel steel, [125]
or case hardening, [79]
pots for, [123]
Carburizing, process of, [ix], [83], [116]
short method, [124]
sleeves, [132]
with charcoal, [81], [88]
See Case hardening
Car door type of furnace, [190]
Case, depth of, [86]
Case hardening boxes, [80]
cast iron, [89]
local, [94]
or surface carburizing, [79]
treatments for various steels, [92]
see Carburizing
Cast iron, carbon in, [ix]
case hardening, [89]
Cementite, [ix], [14]
Center column furnace, [186]
Centigrade table, [232-234]
Chamotte tubes, [228]
Chart of carbon penetration, [97]
heat treatment, [151]
shape, [151]
Chrome steel, [26-27]
Chrome-nickel steel, [27-28]
steel, forging, [66]
Chrome-vanadium steel, [28]
Chromium, [26-27]
steels, S. A. E., [41]
Chromium-cobalt steel, [178]
Chromium-vanadium steel, S. A. E., [41]
Classification of steel, [10]
Clay tubes, [229]
Cold end compensator, [213]
junction errors, [222]
shortness, [15], [166]
worked steel, [65]
Color in tempering, [157]
Colors on carbon steels, [163]
Combination tank, [90]
Comparison of fuels, [191]
Compensating leads, [222]
Compensator for cold ends, [214]
automatic, [214]
Composition of steel, [13]
Compound, blending, [103]
separating from work, [102]
Compounds for carburizing, [102]
Connecting rods, Liberty motor, [42], [52]
Continuous heating furnace, [71]
Converter, Bessemer, [2]
Cooling curves, [106], [107]
Cooling quenching oil, roof system, [74]
rate of, for gear-forgings, [51]
Copper, effect of, in medium carbon steel, [35]
Copper-plating to prevent carburizing, [93]
Corrosion of high-chromium steel, [38]
of rust-proof steel, [38]
Corundite tubes, [229]
Cost of operating furnaces, [200]
Cracks in hardening, preventing, [106]
Crankshaft, Liberty motor, [54]
Critical point, [105]
Crucible or tool steel, [x], [4]
Cutting off high speed steel, [172]
Cyanide bath for tool steel, [133]

Decarbonizing of outer surface, [153]
preventing, [154]
Depth of case, [86]
Detrimental elements in steel, [166]
Dies, drop forging, [133]
quenching, [147]
soft spots in, [147]
tempering round, [161]
Drawing, [114]
ends of gear teeth, [127]
Drop forging dies, [133]
Ductility, [13], [18]

Effect of alloys, [24]
of different carburizing material, [87]
of size of piece, [89], [119]
of copper in medium carbon steel, [35]
Elastic limit, [18]
Electric process of steel making, [5]
Electrode, [5]
Elements, chemical, [12]
Elongation, [18]
Endurance limit, [20]
Energizer, [81], [88]
Enlarging steel, [161]
Equipment for heat treating, [121]
Eutectoid, [109]

Fahrenheit temperature table, [232]
Fatigue test, [19]
Ferrite, [106]
File test, [16], [17]
Flame shields, [193]
Flange shields for furnaces, [197]
Forging furnace, [189]
high speed tools, [174]
improper, [66]
of steel, [64]
practice, heavy, [195]
rifle barrels, [69]
Forgings, carbon steel Liberty engine, [48]
Formed tools, high speed, [174]
Fractures, examining by, [16], [159]
Furnace, continuous heating, [71]
crucible, [4]
data, [199]
electric, [5]
Heroult, [6]
open hearth, [3]
records, [129]
Furnaces, [185]
annealing, [190]
broach hardening, [188]
car door type, [190]
center column, [186]
cost of operating, [200]
data on, [199]
forging, heavy, [195]
fuels for, [199]
gas fired, [190]
high speed steel, [187]
lead pot, [185]
manganese steel, [198]
muffle, [189]
oil fired, [186]
operating costs, [200]
screens for, [192]
tool, [187]
Furnaces, water cooled fronts, [197]
Fuels, comparison of, [191]
for furnaces, [199]

Gages, changes due to quenching, [162]
tempering, [161]
Gamma iron, [106]
Gas, carburizing by, [93]
consumption for carburizing, [101]
fired furnace, [190]
illuminating, for carburizing, [97]
Gear blanks, heat treatment of, [115]
forgings, rate of cooling for Liberty engine, [51]
hardening machine, [130]
steel, transmission, [59]
teeth, drawing ends of, [127]
Gears, Liberty engine, [50]
Gleason tempering machine, [129]
Grade of steel, [10]
Grain, refining, [91], [110]
size, [16]
Graphitic carbon, [ix]
Grinding high speed steel, [176]

Hair lines in forgings, [56]
Hardening, [111]
carbon steel for tools, [145]
cracks, preventing, [160]
dies, [146]
gears, [130]
high speed steel, [171]
high speed tools, [177]
of high-chromium steel, [37]
of rust-proof steel, [37]
room, modern, [146]
Hardness tests, [20]
Heating, effect of size, [119]
for forging, [64]
Heat, judging by color, [114]
treating departments, [122]
equipment, [121]
forgings, [44]
inspection of, [125]
Liberty motor, [44]
Heat treating, of axles, [61]
of chisels, [151]
of gears, [131]
of high speed steel, [170]
of steel, [105]
S. A. E., [134-137]
Heat treatment, [105]
Heroult furnace, [6]
High-chromium steel, [36]
annealing of, [36]
corrosion of, [38]
hardening of, [37]
Highly stressed parts of Liberty engine, [49]
High speed steel, analysis of, [166]
annealing, [75]
cutting off, [172]
forging, [65]
furnace, [187]
hardening, [171]
heat treatment of, [170]
instructions for, [175], [180]
manufacture, [166], [169]
pack hardening, [172]
structure of, [168]
Hints for steel users, [159]

Illuminating gas for carburizing, [97]
Impact test, [19]
Improper forging, [66]
Influence of size on heating, [119]
Inspection of heat treatment, [125]
Internal stresses, relieving, [154]
Introduction of carbon, [96]

Jewelers' tools, [146]
Judging heat of steel by color, [114]

Latent heat, [105]
Lathe and planer tools, [176]
tools, high speed, [173]
Latrobe temper list, [150]
Lead bath, [154]
pot furnace, [185]
Leeds & Northrup potentiometer [211]
optical pyrometer, [220]
Liberty engine, highly stressed parts of, [49]
Liberty engine materials, application to automotive industry, [46]
motor connecting rods, [42], [52]
motor, crankshaft, [54]
motor piston pin, [57]
Local case hardening, [94]
Luting mixture, [100]

Machineability of steel, [72]
Machinery steel, annealing, [77]
Magnet test, [114]
Making steel in electric furnace, [6]
Manganese, [16], [33], [107]
steel, [29-30]
furnace, [198]
Manufacture of high speed steel, [169]
Marquardt mass tubes, [228]
Martensite, [111]
Medium carbon steel, effect of copper on, [35]
Metallography, [105]
Microphotographs, [109] e. s.
Microscopic examination, [158]
Milling cutters, high speed, [174]
Mixture for luting, [100]
Modern hardening room, [146]
Molten metal pyrometers, [226]
Molybdenum, [32]
Muffle furnace, [189]

Nickel, [24]
Nickel-chromium steel, [27-28]
steels, S. A. E., [40]
Nickel, influence of, on steel, [25]
steel, [24-26]
affinity for carbon, [125]
steels, S. A. E., [39]
Non-homogeneous melting, [24]
Non-shrinking steels, [35]
Normalizing, [114]

Oil bath for tempering, [157]
cooling on roof, [74]
fired furnace, [186]
hardening steel, forging, [66]
steels, [35]
temperature of quenching, [124]
Open hearth furnace, [3]
Operating costs of furnaces, [200]
Outer surface decarbonizer, [153]
Over-heated steel, restoring, [137]
Overheating, [65]
dies, [148]

Pack-hardening, [87]
high speed steel, [173]
Packing work for carburizing, [123]
Paste for hardening dies, [146]
Pearlite, [109], [112]
Penetration of carbon, [95]
carbon, chart of, [97]
in case hardening, [83]
Phosphorus, [15], [33]
Pickling Liberty motor forgings, [44]
Pig iron, [ix]
Piston pin, Liberty motor, [57]
Placing pyrometers, [210]
Planer tools, high speed, [173]
"Points" of carbon in steel, [9]
Potentiometer, Leeds & Northrup, [211]
Pots for carburizing, [123]
Press for testing gears, [126]
Preventing carburization, [93]
cracks in hardening, [160]
Properties of alloy steels, [34]
of alloy steels, table, [34]
of steel, [12]
Protective screens for furnaces, [192]
Puddled iron, [ix]
Punches and chisels, steels for, [151]
Pyrometers, [202]
calibration, [208]
copper ball, [202]
indicating, [219]
inspection, [208]
iron ball, [202]
molten metal, [226]
optical, [206], [220]
placing, [210]
recording, [216]
Siemens, [202]
testing, [209]
water, [203]

Quality and structure of high speed steel, [168]
of steel, [149]
Quenching,
after carburizing, [86-88]
dies in tank, [147]
obsolete method, [148]
oil, temperature of, [124]
tank, [89]
tool steel, [156]

Rate of absorption of carbon, [83]
Recording temperatures, [127]
Red shortness, [14], [166]
Refining the grain, [91], [111]
Regenerative open hearth furnace, [3]
Restoring overheated steel, [137]
Rifle barrels, forging, [69]
components, annealing, [78]
Roof system of cooling oil, [74]
Rust-proof steel, [36]
annealing of, [36]
corrosion of, [38]
hardening of, [37]

S. A. E. carbon steels, [10], [39]
chromium steels, [41]
chromium-vanadium, [41]
heat treatments, [134-137]
nickel-chromium steels, [40]
nickel steels, [39]
screw stock, [39]
silico-manganese steel, [41]
standard steels, [39]
Salt bath for tempering, [157]
Scleroscope test, [21]
Scratch hardness, [20]
Screens for furnaces, [192]
Screw stock, S. A. E., [14], [39]
Sensible heat, [105]
Sentinels, melting of, [207]
Separating work from compound, [102]
Shields for furnace doors, [193]
Shore Scleroscope, [21]
Short method of carburizing, [124]
Shrinking steel, [161]
Silica tubes, [228]
Silico-manganese steels, S. A. E., [41]
Silicon, [15], [33], [107]
Silversmiths' tools, [146]
Size of piece, effect of, [89], [119]
Slags, [7]
Sleeves, carburizing, [132]
hardening and shrinking, [132]
shrinking, [132]
Solid solution, [106]
Sorbite, [112]
Specimens, test, [17]
Standard S. A. E. steels, [39]
Steel,
balls, stock for, [62]
bolts, making, [61]
composition of, [12]
deoxidation, [15]
for chisels and punches, [151]
forging of, [64]
give it a chance, [148]
heat treatment of, [105]
high speed, [165]
making, [1], [6], [15]
Bessemer process, [1]
crucible process, [4]
electric furnace process, [5]
open hearth, [1]
tools, carbon, in, [149]
users' hints, [159]
Structure of high speed steel, [168]
Sulphur, [14], [33]

Tables, air, oil and water hardened steel, [38]
alloy steels, properties of, [34]
carbon content, [84]
carbon steels, [39]
case hardening, [97]
changes due to quenching, [162]
chromium steels, [41]
chromium-vanadium steels, [41]
colors and temperature, [163]
composition of steels, [51], [52]
cost of furnaces, [200]
effect of size, [119]
fuels, comparison of, [191]
high-chromium steel, [37]
nickel-chromium steels, [40]
nickel steels, [39]
operating cost of furnaces, [200]
production cost of furnaces, [201]
S. A. E. steels, [49]
screw stock, [39]
silico-manganese steels, [41]
stock for balls, [62]
temperature conversion, [232-234]
tempering temperatures, [158]
weight of steel, [235-237]
Tank for quenching, [89]
dies, [147]
Taylor instruments, [215]
Temper, colors of, [157]
list, Latrobe, [150]
of steel, [10], [149]
Temperature recorders, [127]
tables, [232-234]
Temperatures for tempering, [158]
Tempering colors on carbon steels, [163]
gages, [161]
high speed tools, [177]
machine, Gleason, [129]
round dies, [161]
temperatures, [158]
theory of, [114], [156]
Tempers of carbon steel, [10], [150]
Tensile test, [17]
Testing heat treatment, [125]
Tests of steel, [16]
Test specimens, [17]
Theory of tempering, [114], [150]
Thermocouple, [204]
base metal, [205]
cold end, [206]
placing, [218]
protectors, [227]
rare metal, [205]
Time for hardening, [148]
Tool furnace, small, [187]
Tool or crucible steel, annealing, [76]
Tool steel, cyanide bath for, [133]
quenching, [150]
Tools, carbon in different, [149]
carbon steel, [145]
of high speed steel, [173]
sulphur in, [14]
tempers of various, [150]
transformation points, [106]
Transmission gear steel, [59]
Treatments for various steels, [92]
Troosite, [112]
Tubes, calorized, [229]
carborundum, [229]
Chamotte, [228]
clay, [229]
Marquardt mass, [228]
silica, [228]
Tungsten steel, [30]

Ultimate strength, [17]
Users of steel, hints for, [159]

Vanadium steel, [28]

Water annealing, [155]
cooled furnace fronts, [197]
Weight of steel bars, [235-237]
Working instructions for high speed steel, [175]
Wrought iron, [ix]

Yield Point, [19]