EN 19 Round Bars

EN 19 hot rolled round bar is a chromium molybdenum through hardening steel used for shafts, axles, gears and spindles.

16 to 125 mm Alloy steel Made to order

HOT ROLLED ROUND BARS

EN 19 hot rolled round bar

EN 19 hot rolled round bar is a chromium molybdenum engineering steel supplied as a rolled round section in 16 to 125 mm diameter. The same steel is designated 709M40 in BS 970, 42CrMo4 in EN 10083-3 and 4140 in ASTM A29 and ASTM A322. Its chromium and molybdenum raise hardenability, so the bar hardens through the middle of a medium section in an oil quench instead of only near the surface. A plain carbon grade such as EN 8 costs less but leaves a soft core at the same diameter. EN 24 adds nickel and holds its strength in heavier sections, so EN 19 is the usual choice while the section stays moderate and the part is machined from bar.

The bar is supplied annealed, normalised, or hardened and tempered to a BS 970 condition such as T, which sets tensile strength at 850 to 1000 MPa. Annealed bar machines freely, and each higher condition cuts more slowly and needs rigid tooling. The steel is magnetic and has no corrosion resistance, so finished parts are plated, painted or kept oiled. Welding calls for preheat and a temper afterwards, because the carbon and chromium harden the weld zone. Parts machined from this bar include drive shafts and axles, gears and pinions, hydraulic cylinder rods, and spindles and tie rods. Laxcon Steels rolls the bar to order, black, spot ground or fully ground.

Composition limits in weight percent are carbon 0.36 to 0.44, manganese 0.7 to 1.0, sulphur 0.05 maximum, phosphorus 0.05 maximum, silicon 0.1 to 0.35, chromium 0.9 to 1.2 and molybdenum 0.25 to 0.35.

SPECIFICATION

EN 19 hot rolled round bar supply conditions

Size range: 16 mm - 125 mm (5/8" - 5")
Length: Up to 8 metres
Tolerances: EN10060
Heat treatment: Soft annealing or normalising; oil or water quenching and tempering
Grade: EN 19 (EN19, 709M40, 42CrMo4, 4140)
Family: Alloy steel
Supply: Made to order in this grade; every published size of the form

Composition of EN 19

Element	Symbol	Minimum %	Maximum %
Carbon	C	0.36	0.44
Manganese	Mn	0.7	1.0
Sulphur	S		0.05
Phosphorus	P		0.05
Silicon	Si	0.1	0.35
Chromium	Cr	0.9	1.2
Molybdenum	Mo	0.25	0.35

Composition, weight percent, balance iron. From the Laxcon Steels grade reference.

Equivalents of EN 19

Standard	Designation
SAE	4140 / 4142
DIN	42CrMo4

Equivalence means nearest counterpart, not identity: each standards body sets its own composition window, so the limits of the standard named on the order govern.

Governing standards

EN 10083-1: Steels for quenching and tempering, part 1: general technical delivery conditions for the bars, rods and sections supplied for heat treatment.
EN 10083-3: Steels for quenching and tempering, part 3: technical delivery conditions for alloy steels, 42CrMo4 and 34CrNiMo6 among them.
BS 970-1: Wrought steels for mechanical and allied engineering purposes, part 1: the British numbering behind the EN and M designations and the R to Z heat treatment conditions.
ASTM A29/A29M: Steel bars, carbon and alloy, hot-wrought: general requirements for delivery, the base every carbon and alloy bar order inherits.
ASTM A322: Steel bars, alloy, standard grades: the composition tables for the SAE alloy grades supplied as bar.
EN 10060: Hot rolled round steel bars for general purposes: dimensions and tolerances on shape and dimensions.
NACE MR0175 / ISO 15156: Materials for use in H2S-containing environments in oil and gas production: the sour-service limits on hardness and condition.
EN 10204: Metallic products, types of inspection documents: the 2.2 test report and the 3.1 and 3.2 inspection certificates a purchase order can call for.

Weight per metre

Diameter (mm)	kg per metre	Metres per tonne
16	1.58	633.5
17	1.78	561.2
18	2.00	500.6
19	2.23	449.3
20	2.47	405.5
21	2.72	367.8
22	2.98	335.1
23.2	3.32	301.3
24	3.55	281.6
25	3.85	259.5
26	4.17	239.9
27	4.49	222.5
28	4.83	206.9
30	5.55	180.2
32	6.31	158.4
34	7.13	140.3
36	7.99	125.1
37	8.44	118.5
38	8.90	112.3
40	9.87	101.4
42	10.88	91.9
45	12.49	80.1
47	13.62	73.4
48	14.21	70.4
50	15.41	64.9
53	17.32	57.7
56	19.34	51.7
57.5	20.39	49.1
60	22.20	45.1
63	24.47	40.9
66	26.86	37.2
67.5	28.09	35.6
70	30.21	33.1
73.5	33.31	30.0
75	34.68	28.8
77.5	37.03	27.0
80	39.46	25.3
83	42.48	23.5
85	44.55	22.4
88	47.75	20.9
90	49.94	20.0
93	53.33	18.8
95	55.65	18.0
98	59.22	16.9
100	61.66	16.2
105	67.98	14.7
106	69.28	14.4
110	74.61	13.4
115	81.54	12.3
120	88.79	11.3
125	96.34	10.4

Density 7.85 g/cm³, diameter squared x 0.006166. Sizes are the published range at the nominal diameters shown.

Ordering EN 19 hot rolled round bar

An enquiry for this grade in this form states the grade with its governing standard, EN 19 to BS 970 or 42CrMo4 to EN 10083-3, the condition required, the diameter with the tolerance standard and class to EN 10060 or ASTM A484, the length, the quantity, the surface wanted, and the test certificate type to EN 10204. Ultrasonic testing and PMI confirmation of the grade are stated in the same place.