Hardness range of steel (steel pipe) used in thermal power plants
 
The steel used in thermal power plants is mainly used in the four major pipelines of thermal power plants.
The four major pipelines of a thermal power plant include: a main steam pipeline, a high temperature reheat steam pipeline, a low temperature reheat steam pipeline, and a high pressure water supply pipeline.
Therefore, the steel (steel pipe) commonly used in thermal power plants must meet the requirements for the use of the four major pipelines.
 
Commonly used steel (steel pipe) material for thermal power plants:
SA210 C, SA234-WPC, SA234-WPB, 20MnMo, 15MnMoV, SA209 T1, SA182 F1, SA234-WP111, SA234-WP121, A691-11 / 4Cr, SA213-T2, SA182-F2, SA182-F12, A213 T11, A213 T12, A213 T23, SA182-F22, 1Cr5Mo, A213 T91, A213 T92,1Crl3, OCrl3A1,1Crl8Ni9,0Cr23Ni13, 0Cr23Ni13, l0, 20, 12Cr2Mo, 10CrMoV, 15CrMo, 15CrMo, ZGZOCrMoV, ZG15Cr1Mo1V, 12Cr1MoV, Cr2Mo1, SA213 T9 , 10CrMo9lO and so on.

Hardness power plant common steel hardness range chart

Steel				Grade		Hardnes	Standard
Steel pipe used in thermal power plants	1			SA210C		HB≤179	ASTM A210
	2			SA234-WPC		HB≤197	ASTM A234
	3			SA234-WPB		HB≤197	ASTM A234
	4			20MnMo		HB149～217	JB755
	5			15MnMoV		HB156～228	JB755
	6			SA209T1		HB≤146	ASTM A209
	7			SA182F1		HB143～192	ASTM A182
	8			SA234-WP111		HB≤197	ASTM A234
	9			SA234-WP121		HB≤197	ASTM A234
	l0			T1		HB≤146	ASTM A209
	11			A691-11/4Cr		HB≤201	ASTM A691
	l2			SA213-T2		HB≤217	ASTM A213
	l3			SA182-F2		HB143～192	ASTM A182
	l4			SA182-F12		HB 121～174	ASTM A182
	l5			T11		HB≤163	ASTM A213
	l6			T12		HB≤163	ASTM A213
	l7			T23		HB≤220	ASTM A213
	l8			SA182-F22		HB≤170	ASTM A182
	l9			1Cr5Mo		HB 156～241	JB755
	2O			T9l		HB≤250	ASTM A213
	2l			T92		HB≤250	ASTM A213
	22			1Crl3		HB≤159	GB 1220
	23			OCrl3A1		HB≤183	GB 1220
	24			1Crl8Ni9		HB≤187	GB 1220
	25			0Cr23Ni13		HB≤187	GB 1220
	26			1Cr18Ni9Ti		HB≤187	GB 1220
	27			l0		HB≤137	GB3087
	28			20		HB≤156	GB3087
	29			12Cr2Mo		HB≤170	GB5310
	30			10CrMoV		HB≤166	GB5310
	3l			15CrMo		HB≤179	GB5310
	32			ZG20CrMo		HB 135～140	DJ156
	33			ZGZOCrMoV		HB135～140	JB264O
	34			ZG15Cr1Mo1V		HB2OO～255	JB264O
Straight, Bent pipe, Steam guide	1			12Cr1MoV		HB≤170
	2			Cr2Mo1		HB≤170
	3			SA213:T9		HB≤179
	4			SA213: other		HB≤163
Alloy steel header	1			12Cr1MoV		HB≤170
	2			10CrMo9lO		HB≤170
Weld	The weld of the same kind of steel welded joints is generally not more than 100 times of the base material HB after heat treatment; For non-austenitic welds of welded joints in heterogeneous port, the hardness after heat treatment generally does not exceed the height of high alloy steel base material HB plus 100; both must meet the following requirements:
	l		Total alloy content <3%			HB≤270	The same kind of steel: DL/T 869-2012 Dissimilar steel: DL/T 752-2010
	2		Total alloy content  3%～10%			HB≤300
	3		Total alloy content >10%			HB≤350
	Note: Dissimilar steel calculates the total alloy content from the composition of the base material with low alloy content.
Turbine rotor	l	25Cr2Ni4MoV				HB230～260 (236～286)
	2	34CrNi3Mo				HB240～270
	3	30Cr2MoV(P2)				HB255～321 (241～277)
	4	30Cr1Mo1V				HB250～280	JB/T 1265
High temperature bolt	l	35				HB146～187	DL439-91
	2	45				HB187～227
	3	20CrMo				HB197～241
	4	35CrMo				HB217～255
	5	20Cr1MolV1				HB248～277
	6	20Cr1MolVTiB				HB255～293
	7	25Cr2Mo1V				HB241～277
						HB240～290	DL438-2009
	8	25Cr2MoV				HB241～277	DL439-91
						HB240～290
	9	C422(20Cr12NiMoWV)				HB277～331
	l0	R26(Ni-Cr-Co alloy)				HB262～331
	11	20Cr1Mo1VNbTiB				HB241～285	DL439-91
						HB240～290	DL438-2009
	l2	W4OCrMoV				HB255～321
	13	42CrMo				HB248～311
	l4	K11C81E-R0(High alloy steel)				HB291～321	DL438-2009
	15	GH4145/SQ(alloy)				HB262～331
Steam turbine bolt	1	30CrMoA			Rm（σb）≥686Mpa	HB217～255	Steam turbine
					Rm（σb）≥784Mpa	HB241～277
					Rm（σb）≥862Mpa	HB277～302
	2	30Cr2MoV			Rm（σb）≥735Mpa	HB241～277
					Rm（σb）≥833Mpa	HB269～302
Note: The nut material is generally one level lower than the bolt material, and the hardness is 20~50HB.

 
Detailed explanation:
T91 190～250
T22 130～179
 
Standard GB3077-88
The hardness of 12Cr1MoV steel is not more than 179 in the annealing or high temperature tempering supply state.
The hardness range of 25Cr2Mo1V as steel for bolts is: HB241--277
35 steel The hardness range of steel used as bolts is: HB146--187
20Cr1Mo1VTiB as a bolt steel hardness range: HB255--293
 
Standard GB699-88
20 steel delivery state hardness HB is not greater than 156
30 steel delivery state hardness HB is not more than 170
35 steel delivery state hardness HB is not greater than 179

Common bolt material hardness standards

Grade	Hardness	Note
K11C81E-Ro	HB291～HB321	High alloy steel
GH4145/SQ	HB262～HB331	Alloy steel
C-422（20Cr12NiMoWV）	HB277～HB331	High alloy steel
R26（Ni-Cr-Co)	HB262～HB331	Alloy steel

 New bolts of 20Cr1Mo1VNbTiB steel after quenching and tempering, hardness is HB240～HB290;
After the operation of the 25Cr2Mo1V and 25Cr2MoV steel bolts, the test results should be in accordance with the hardness of HB240 ~ HB290;

Standard SA234 (forged carbon steel and alloy steel pipe fittings for medium and high temperature)
For WP5, WP9 and WPR grade steel pipe fittings - up to 217HB.
For WP91 grade steel pipe fittings - up to 248HB.
For other grades of steel fittings - up to 197HB.
 
Standard SA213 (seamless ferrite and austenitic alloy tubes for boilers, superheaters and heat exchangers T)
The hardness of T5b, T7 and T9 grade steel shall not exceed 179HB/190HV (89HRB), the hardness of T91 and T92 grade steel shall not exceed 250HB/265HV (25HRC), and the hardness of 18Cr-20Mo grade steel shall not exceed 217HB/230HV ( 96HRB),
 
All other ferrite grade hardnesses should not exceed 163HB/170HV (85HRB).
The hardness of TP201 and TP202 grade steel should not exceed 219HB/230HV (95HRB).
Tubes made from S30815, S31272, S31050 and S25700 have a Brinell hardness of no more than 217 HB (95 HRB).
 
The Brinell hardness of pipes made of TP310HCbN grade steel shall not exceed 256 HB (100 HRB).
The hardness of XM-19 (UNS S20910) grade steel should not exceed 250HB/265HV (25HRC).
The hardness of all other austenitic grade steels shall not exceed 192HB/200HV (90HRB).
 
Standard SA210 (seamless medium carbon steel tube for boiler and overheating T)
The hardness of the A-1 grade pipe shall not exceed the Rockwell hardness of 79 HRB or the Brinell hardness of 143 HB.
The hardness of the Class C pipe shall not exceed 89 Rockwell hardness or 179 HBB hardness.
 
Other:
10CrMo910 corresponds to China's grade 10Cr2Mo1. The US grade is SA213T22 (ASTM). According to DIN EN 10028-1/2, 10CrMo910 and P22 have a hardness range of 130-175HB.
Soviet grades 22K and 20K correspond to Chinese grades 22g and 20g; US grades are SA414E and SA414D
 
Weld hardness standard:
The weld hardness of the same kind of steel welded joint after heat treatment generally does not exceed the Brinell hardness of the base metal plus 100HBW, and does not exceed the following provisions:
When the total content of the alloy is <3%, the Brinell hardness value is ≤270HBW
When the total content of the alloy is 3%-10%, the Brinell hardness value is ≤300HBW
When the total content of the alloy is >10%, the Brinell hardness value is ≤350HBW
Weld hardness test of dissimilar steel welded joints shall comply with the provisions of DL/T752.
The hardness of the heat-resistant alloy steel weld is not lower than the hardness of the base metal.
 
Weld metallographic organization standards:
1, no cracks;
2. There is no burnt tissue;
3. There is no hardened martensite structure.
 
Specification for welding process qualification of boiler and pressure vessel in thermal power plants (SD340-89)
The hardness of the weld and heat affected zone generally does not exceed the Brinell hardness of the parent metal plus 100
Steel with chromium content <2%, HB≤250
Steel with chromium content ≥2%, HB≤300
Metal fusion welding weld defect classification and description GB6417-86
Metal fusion weld weld defects are classified into six categories: cracks, holes, solid inclusions, unfused and incomplete, and shape defects.
Unfused is divided into: the side wall is not fused, the layers are not fused, and the root of the weld is not fused.