Item specifics

CF8M / AISI316 / 1.4408 Stainless Steel
Lost Wax Precision Investment Casting + CNC Machin
Butterfly Valve Disc
Available Heat Treatment
Annealing, Solution



OBT is a China stainless steel casting foundry to have the stainless steel castings machined as per your drawings and requirements, used for butterfly valve disc.

CNC machining refers to the machining process proceed by Computerized Numberical Control (CNC for short). It is aided by the CNC to reach a high and steady accuracy with less labor cost. Machining is any of various processes in which a piece of raw material is cut into a desired final shape and size by a controlled material-removal process. The processes that have this common theme, controlled material removal, are today collectively known as subtractive manufacturing, in distinction from processes of controlled material addition, which are known as additive manufacturing.

China precision stainless steel casting company

Exactly what the “controlled” part of the definition implies can vary, but it almost always implies the use of machine tools (in addition to just power tools and hand tools). This is a process used to manufacture many metal products, but it can also be used on materials such as wood, plastic, ceramic, and composites. The CNC machining covers many different processes such as milling, turning, lathing, drilling, honing, grinding...etc.

casting pump and valve spare parts


CNC Precision Machining Capabilities
FacilitiesQuantitySize RangeAnnual CapacityGeneral Accuracy
Vertical Machining Center (VMC)48 sets1500mm × 1000mm × 800mm6000 tonn or 300000 pieces±0.005
Horizontal Machining Center (VMC)12 sets1200mm × 800mm × 600mm2000 tons or 100000 pieces±0.005
CNC Machine60 setsMax turning dia. φ600mm5000 tons or 600000 pieces  
Excutive Standard of Casting Tolerance: ISO 8062 2013, ISO 2768, GOST 26645 (Russia) or GBT 6414 (China).

The machining center is developed from the CNC milling machine. The biggest difference from the CNC milling machine is that the machining center has the ability to automatically exchange machining tools. By installing tools for different purposes on the tool magazine, the machining tools on the spindle can be changed by the automatic tool changer in one clamping to realize multiple machining features.

The CNC machining center is a high-efficiency automated machine tool that is composed of mechanical equipment and a CNC system and is suitable for processing complex parts. The CNC machining center is currently one of the most widely used CNC machine tools in the world with strong comprehensive processing ability. It can complete more processing content after the workpiece is clamped at one time. The processing accuracy is high. For batch workpieces with medium processing difficulty, its efficiency is 5-10 times that of ordinary equipment, especially it can complete Many processings that cannot be completed by ordinary equipment are more suitable for single-piece processing with more complex shapes and high precision requirements or for small and medium batch production of multiple varieties. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one device, so that it has a variety of technological means.

Machining centers are classified into horizontal and vertical machining centers according to their spatial position during spindle machining. Classified according to process use: boring and milling machining center, compound machining center. According to the special classification of functions, there are: single workbench, double workbench and multi-workbench machining center. Machining centers with single-axis, dual-axis, three-axis, four-axis, five-axis and interchangeable headstocks, etc.

CNC machining is the kind of precision machining by CNC machines such as advanced machining centers which have top end 5 axis machining center, 4 axis double platform machining center, or CNC turning lathes which can also be developed to CNC turning center having capability of changing more than 15 cutters within one holding shift; CNC milling machine and CNC drilling and tapping centers.Precision machining of steel casting is different from machining of steel profile. Precision casting has already achieve quite exact shape of what is desired, thus it saves lots of machining compared with machining from steel profile directly. Also because of this reason, we usually have to consider machining surface and proper machining allowance before casting. Our regular procure is to work out raw casting drawing along with machining drawing to specify machining area and machining allowance on the drawing.

OBT investment casting foundry has equipped with 4 axis machining centers, 15 sets of CNC turning lathes and 3 sets of cnc milling machines, along with assistant common versatile turning, milling, tapping, drilling and grinding machines, we have the capability of machining nearly all kinds of steel castings.

Equivalent Grade of Cast Alloy Steel from Different Markets
Low Alloy Steel92551.090455 Si 7250 A 53209055 S 756Si7-5SSi8
13351.116736 Mn 5150 M 36212040 M 536Mn5SMn 438(H)-
13301.117028 Mn 6150 M 28-20 M 5-SCMn1C28MN
P41.2341X6 CrMo 4------
521001.3505100 Cr 6534 A 992258100 C 6F.131SUJ 2100Cr6
A204A1.541515 Mo 31501 240291215 D 316 Mo3STBA 1216Mo3 KW
86201.652321 NiCrMo 2805 M 20250620 NCD 2F.1522SNCM 220(H)20NiCrMo2
87401.654640NiCrMo22311-Type 7-40 NCD 2F.129SNCM 24040NiCrMo2(KB)
-1.658717CrNiMo6820 A 16-18 NCD 614NiCrMo13--
51321.703334 Cr 4530 A 32-32 C 435Cr4SCr430(H)34Cr4(KB)
51401.703541 Cr 4530 A 40-42 C 242 Cr 4SCr 440 (H)40Cr4
51401.703541 Cr 4530 A 40-42 C 242 Cr 4SCr 440 (H)41Cr4 KB
51401.704542 Cr 4530 A 40224542 C 4 TSF.1207SCr 440-
51151.713116 MnCr 5(527 M 20)251116 MC 5F.1516-16MnCr5
51551.717655 Cr 3527 A 60225355 C 3-SUP 9(A)55Cr3
41301.721825 CrMo 41717CDS 110222525 CD 4F.1251/55Cr3SCM 420 / SCM43025CrMo4(KB)
4135 (4137)1.722035 CrMo 4708 A 37223435 CD 434 CrMo 4SCM 43234CrMo4KB
41421.722341 CrMo 4708 M 40224442 CD 4 TS42 CrMo 4SCM 44041 CrMo 4
41401.722542 CrMo 4708 M 40224440 CD 4F.1252SCM 44040CrMo4
41371.722542 CrMo 4708 M 40224442 CD 4F.1252SCM 44042CrMo4
A387 12-21.733716 CrMo 4 41501 620221615 CD 4.5--12CrMo910
-1.736132CrMo12722 M 24224030 CD 12F.124.A-30CrMo12
A182 F-221.738010 CrMo9  101501 622221812 CD 9, 10F.155 / TU.H-12CrMo9 10
61501.815950 CrV 4735 A 50223050 CV 4F.143SUP 1050CrV4
-1.851531 CrMo 12722 M 24224030 CD 12F.1712-30CrMo12
Medium Alloy Steel W11.1545C105W1BW1A1880Y 105F.5118SK 3C100 KU
L31.2067100Cr6BL 3(2140)Y 100 C 6F.520 L--
L21.2210115 CrV 3------
P20 + S1.231240 CrMnMoS 8 6--40 CMD 8 +SX210CrW12--
-1.2419105WCr6-2140105W C 13F.5233SKS 31107WCr5KU
O11.2510100 MnCrW 4BO1-90MnWCrV5F.5220(SK53)95MnWCr5KU
S11.254245 WCrV 7BS1271055W20F.5241-45WCrV8KU
43401.658234 CrNiMo 6817 M 40254135 NCD 6F.1280SNCM 44735NiCrMo6KB
51201.714720 MnCr 5--20 MC 5---
Tool and High Alloy SteelD31.2080X210 Cr 12BD32710Z200 C 12F.5212SKD 1X210Cr13KU
P201.231140 CrMnMo 7--40 CMD 8F.5263--
H131.2344X40CrMoV 5 1BH132242Z 40 CDV 5F.5318SKD 61X40CrMoV511KU
A21.2363X100 CrMoV 5 1BA22260Z 100 CDV 5F.5227SKD 12X100CrMoV51KU
D21.2379X155 CrMoV 12 1BD22310Z 160 CDV 12F.520.ASKD11X155CrVMo121KU
D4 (D6)1.2436X210 CrW 12BD62312Z 200 CD 12F.5213SKD 2X215CrW121KU
H211.2581X30WCrV9 3BH21-Z 30 WCV 9F.526SKD5X30WCrV 9 3 KU
L61.271355NiCrMoV 6--55 NCDV 7F.520.SSKT4-
M 351.3243S6/5/2/5BM 3527236-5-2-5F.5613SKH 55HS6-5-5
M 21.3343S6/5/2BM22722Z 85 WDCVF.5603SKH 51HS6-5-2-2
M 71.3348S2/9/2-27822 9 2--HS2-9-2
HW 31.4718X45CrSi 9 3401 S 45-Z 45 CS 9F.3220SUH1X45CrSi8
-1.732120 MoCr 4-2625-F.1523-30CrMo4
High Tensile Strength SteelA128 (A)1.3401G-X120 Mn 12BW102183Z 120 M 12F.8251SCMnH 1GX120Mn12

Capabilities of Investment Casting Foundry:
• Max Size: 1,000 mm × 800 mm × 500 mm
• Weight Range: 0.5 kg - 100 kg
• Annual Capacity: 2,000 tons
• Bond Materials for Shell Building: Silica Sol, Water Glass and their mixtures.
• Tolerances: On Request.

Advantages of Investment Casting Components:
- Excellent and smooth surface finish
- Tight dimensional tolerances.
- Complex and intricate shapes with design flexibility
- Capability to cast thin walls therefore a lighter casting component
- Wide selection of cast metals and alloys (ferrous and non-ferrous)
- Draft is not required in the molds design.
- Reduce the need for secondary machining.
- Low material waste.


Materials for Investment Casting and CNC Machining at OBT Foundry
CategoryChina GradeUS GradeGermany Grade
Ferritic Stainless Steel1Cr17, 022Cr12, 10Cr17, 430, 431, 446, CA-15, CA6N, CA6NM1.4000, 1.4005, 1.4008, 1.4016, GX22CrNi17, GX4CrNi13-4
Martensitic Stainless Steel1Cr13, 2Cr13, 3Cr13, 4Cr13, 410, 420, 430, 440B, 440C1.4021, 1.4027, 1.4028, 1.4057, 1.4059, 1.4104, 1.4112, 1.4116, 1.4120, 1.4122, 1.4125
Austenitic stainless steel06Cr19Ni10, 022Cr19Ni10,
06Cr25Ni20, 022Cr17Ni12Mo2, 03Cr18Ni16Mo5
302, 303, 304, 304L, 316, 316L,   329, CF3, CF3M, CF8, CF8M, CN7M, CN3MN1.3960, 1.4301, 1.4305, 1.4306, 1.4308, 1.4313, 1.4321, 1.4401, 1.4403, 1.4404, 1.4405, 1.4406, 1.4408, 1.4409, 1.4435, 1.4436, 1.4539, 1.4550, 1.4552, 1.4581,
1.4582, 1.4584, 
Precipitation Hardening Stainless Steel05Cr15Ni5Cu4Nb, 05Cr17Ni4Cu4Nb630, 634, 17-4PH, 15-5PH,  CB7Cu-11.4542
Duplex Stainless Steel022Cr22Ni5Mo3N, 022Cr25Ni6Mo2NA 890 1C, A 890 1A, A 890 3A, A 890 4A, A 890 5A,
A 995 1B, A 995 4A, A 995 5A, 2205, 2507
1.4460, 1.4462, 1.4468, 1.4469, 1.4517, 1.4770
High Mn SteelZGMn13-1, ZGMn13-3, ZGMn13-5B2, B3, B41.3802, 1.3966, 1.3301, 1.3302
Tool SteelCr12A5, H12, S51.2344, 1.3343, 1.4528, GXCrMo17,   X210Cr13, GX162CrMoV12
Heat Resistant Steel20Cr25Ni20, 16Cr23Ni13,
309, 310, CK20, CH20, HK301.4826, 1.4828, 1.4855, 1.4865
Nickle-base Alloy HASTELLY-C, HASTELLY-X,  SUPPER22H, CW-2M, CW-6M, CW-12MW, CX-2MW, HX(66Ni-17Cr), MRE-2, NA-22H, NW-22,  M30C, M-35-1, INCOLOY600,
2.4815, 2.4879, 2.4680
ZL101, ZL102, ZL104ASTM A356, ASTM A413,  ASTM A360G-AlSi7Mg, G-Al12
Copper AlloyH96, H85, H65, HPb63-3,
HPb59-1, QSn6.5-0.1, QSn7-0.2
C21000, C23000, C27000, C34500, C37710, C86500,  C87600, C87400, C87800,  C52100, C51100CuZn5, CuZn15, CuZn35, CuZn36Pb3, CuZn40Pb2, CuSn10P1, CuSn5ZnPb, CuSn5Zn5Pb5
Cobalt-base Alloy UMC50, 670, Grade 312.4778

Also called precision machining, the CNC machining could reach a very high accuracy in geometical tolerance and dimensional tolerance. With our CNC machines and Horizontal Machining Centers (HMC) and Vertical Machining Centers (VMC), we can almost meet all of your required tolerance grades. 


Up to 0.500±.004"Up to 12.0± 0.10mm
0.500 to 1.000”±.006"12.0 to 25.0± 0.15mm
1.000 to 1.500”±.008"25.0 to 37.0± 0.20mm
1.500 to 2.000”±.010"37.0 to 50.0± 0.25mm
2.000  to 2.500”±.012"50.0 to 62.0± 0.30mm
2.500 to 3.500”±.014"62.0 to 87.0± 0.35mm
3.500 to 5.000”±.017"87.0 to 125.0± 0.40mm
5.000 to 7.500”±.020"125.0 to190.0± 0.50mm
7.500 to 10.000”±.022"190.0 to 250.0± 0.57mm
10.000 to 12.500”±.025"250.0 to 312.0± 0.60mm
12.500 to 15.000±.028"312.0 to 375.0± 0.70mm
AISI 316 Stainless Steel Machining Impeller
cnc machined metal services
stainless steel casting pump end cover
Alloy steel 20Mn machined parts