4130 vs 4140 steel: everything you want to know

4130 vs 4140 steel: let’s compare فولاذ 4130 and AISI فولاذ 4140, drawing directly. Both are classified as medium-carbon, low-alloy steels and belong to the chromium-molybdenum alloy steel family.

التركيب الكيميائي

4130 vs 4140 steel: composition comparison

العنصر	AISI 4130 (wt%)	AISI 4140 (wt%)	ملحوظات
الكربون	0.28-0.33	0.38-0.43	Higher carbon content in 4140
المنغنيز	0.40-0.60	0.75-1.00	Higher manganese content in 4140
السيليكون	0.20-0.35	0.20-0.35
الكروم	0.80-1.10	0.80-1.10
الموليبدينوم	0.15-0.25	0.15-0.25

الخصائص الميكانيكية

4130 vs 4140 steel: properties comparison. The mechanical properties are highly dependent on the heat treatment applied and the material’s section size. The data in this section is directly quoted from ASM International. (1991). دليل ASM، المجلد 4: المعالجة الحرارية (pp. 500-503). ASM International.

Typical mechanical properties of heat-treated 4130 steel.

Tempering temperature		قوة الشد		قوة الخضوع		الاستطالة في 50 مم (2 بوصة)، %	انخفاض في المساحة، %	الصلابة، HB	Izod impact energy
درجة مئوية	درجة فهرنهايت	ميجا باسكال	كسي	ميجا باسكال	كسي
Water quenched and tempered. 25 mm (1 in.) diam round bars quenched from 845 to 870 °C (1550 to 1600 °F).
205	400	1765	256	1765	1520	10	33	475	18	13
260	500	1670	242	1670	1430	11.5	37	455	14	10
315	600	1570	228	1570	1340	13	41	425	14	10
370	700	1475	214	1475	1250	15	45	400	20	15
425	800	1380	200	1380	1170	16.5	49	375	34	25
540	1000	1170	170	1170	1000	20	56	325	81	60
650	1200	965	140	965	830	22	63	270	135	100
Oil quenched and tempered. 25 mm (1 in.) diam round bars quenched from 860 °C (1575 °F).
205	400	1550	225	1340	195	11	38	450	/	/
260	500	1500	218	1275	185	11.5	40	440	/	/
315	600	1420	206	1210	175	12.5	43	418	/	/
370	700	1320	192	1120	162	14.5	48	385	/	/
425	800	1230	178	1030	150	16.5	54	360	/	/
540	1000	1030	150	840	122	20	60	305	/	/
650	1200	830	120	670	97	24	67	250	/	/

تأثير الكتلة على الخصائص النموذجية للفولاذ 4130 المعالج حرارياً

Bar size (mm)	Bar size (in.)	Tensile strength (MPa)	Tensile strength (ksi)	Yield strength (MPa)	Yield strength (ksi)	الاستطالة في 50 مم (2 بوصة)، %	انخفاض في المساحة، %	صلابة السطح، HB
25	1	1040	151	880	128	18	55	307
50	2	740	107	570	83	20	58	223
75	3	710	103	540	78	22	60	217

Note: Round bars oil quenched from 845 °C (1550 °F) and tempered at 540 °C (1000 °F); 12.83 mm (0.505 in.) diam tensile

Typical mechanical properties of heat-treated 4140 steel

Tempering temperature (°C)	Tempering temperature (°F)	Tensile strength (MPa)	Tensile strength (ksi)	Yield strength (MPa)	Yield strength (ksi)	الاستطالة في 50 مم (2 بوصة)، %	انخفاض في المساحة، %	الصلابة، HB	Izod impact energy (J)	Izod impact energy (ft·lb)
205	400	1965	285	1740	252	11	42	578	15	11
260	500	1860	270	1650	240	11	44	534	11	8
315	600	1720	250	1570	228	11.5	46	495	9	7
370	700	1590	231	1460	212	12.5	48	461	15	11
425	800	1450	210	1340	195	15	50	429	28	21
480	900	1300	188	1210	175	16	52	388	46	34
540	1000	1150	167	1050	152	17.5	55	341	65	48
595	1100	1020	148	910	132	19	58	311	93	69
650	1200	900	130	790	114	21	61	277	112	83
705	1300	810	117	690	100	23	65	235	136	100

Effects of mass on typical properties of heat-treated 4140 steel

Diameter of bar (mm)	Diameter of bar (in.)	Tensile strength (MPa)	Tensile strength (ksi)	Yield strength (MPa)	Yield strength (ksi)	الاستطالة في 50 مم (2 بوصة)، %	انخفاض في المساحة، %	صلابة السطح، HB
25	1	1140	165	985	143	15	50	335
50	2	920	133	750	109	18	55	202
75	3	860	125	655	95	19	55	293

Note: Round bars oil quenched from 845 °C (1550 °F) and tempered at 540 °C (1000 °F); 12.83 mm (0.505 in.) diam tensile specimens cut from center of 25 mm diam bars and from midradius of 50 and 75 mm diam bars

Heat Treatment Procedures

4140 Heat Treatment

1. Normalizing: Heat to 870 to 925 °C (1600 to 1700 °F) and hold for a minimum of 1 hour or 15 to 20 minutes per 25 mm (1 in.) of maximum section thickness; air cool. Tempering at 480 °C (900 °F) or above is often performed after normalizing to decrease yield strength.
2. التلدين: Heat to 830 to 870 °C (1525 to 1600 °F) and hold for a period dependent on section thickness or furnace load; furnace cool at about 15 °C/h (30 °F/h) to 480 °C (900 °F) and then air cool.
3. إخماد: It’s a water-hardening alloy steel.

4130 heat treatment

1. Normalizing: Heat to 845 to 925 °C (1550 to 1700 °F) and hold for 1-hour minimum or 15 to 20 minutes per 25 mm (1 in.) of maximum section thickness; air cool.
2. Annealing: Heat to 830 to 870 °C (1525 to 1600 °F) and hold for a period dependent on section thickness or furnace load; furnace cool at about 15 °C/h (30 °F/h) to 480 °C (900 °F) and then air cool.
3. Quenching: Oil-quenched from 855 °C (1575 °F) or 845 °C (1550 °F).
4. Tempering: Has a simple tempering cycle, with 350°F (175 °C) commonly used. To avoid blue brittleness, 4140 is usually not tempered between 230 and 370 °C (450 to 700 °F). Tempering temperature and time depend on the desired hardness.

ملخص

Based on their characteristics and usage experience, here is a summary of the differences between 4140 and 4340 steel.

4140, with its higher carbon and manganese content, generally offers greater hardenability and higher strength compared to 4130. This makes 4140 suitable for applications requiring higher strength in heavier sections, assuming appropriate heat treatment. 4140 has better hardenability, but requires a milder quenching process than 4130 to achieve the same quenching effect on parts with the same geometry. 4140 has a certain probability of cracking and deformation due to excessive cooling speed during the quenching process. When quenching 4140, it is essential to control the quenching parameters strictly.

For thin sections, a plain carbon steel might suffice, while for heavier sections requiring hardening, 4140 would be needed. However, selecting a more expensive alloy like 4340 (which has even higher hardenability due to Nickel-Chromium-Molybdenum) might be unnecessary if 4140 is adequate. Generally, steels with Cr-Ni-Mo are most expensive, followed by Cr-Mo, then Cr-V.