| Steel Grade | Chemical Composition % | |||||||
| C | Si | Mn | Cr | Ni | Mo | S | P | |
| ZG25CrNiMo | 0.25-0.30 | 0.20-0.40 | 0.70-0.90 | 0.40-0.70 | 0.40-0.70 | 0.15-0.25 | ≦0.025 | ≦0.025 |
| ZG30CrMo | 0.26-0.33 | 0.17-0.37 | 0.40-0.70 | 0.80-1.10 | — | 0.15-0.25 | ≦0.025 | ≦0.025 |
| ZG35CrMo | 0.32-0.40 | 0.17-0.37 | 0.40-0.70 | 0.80-1.10 | — | 0.15-0.25 | ≦0.025 | ≦0.025 |
| Standard | Yield Strength Rp0.2 /MPa | Tensile Strength Rb / MPa | Elogation A / % | Reduction of Area Z/ ％ |
| 60K | ≥414 | ≥586 | ≥18 | ≥35 |
| 75K | ≥517 | ≥655 | ≥18 | ≥35 |
| 80K | 585-660 | ≥725 | ≥18 | ≥35 |
Normally we will follow 75K standard.
Production Process | Method | Remark |
Pattern Making | Dimension Inspection for the pattern | Done by engineer |
Melting | Chemical composition before and after pouring | |
Casting in blank | VT | |
Heat treatment | Test sample with castings | Mechanical Property |
Before first rough machining | Check the dimension and drawing the line | |
After rough machining | UT and MT | |
Semi-finished machining | UT and MT | |
Finished machining | UT and MT |
| No. | Equipment Name | Quantity(Set) |
| 1 | Transformer substation | 1 |
| 2 | Full set of wooden molding equipment | 10 |
| 3 | Sodium silicate sand mix line | 4 |
| 4 | Alkaline phenol resin sand mix line | 2 |
| 5 | 25 tons Electric arc furnace | 1 |
| 6 | 50 tons Intermediate frequency furnace | 2 |
| 7 | 120 tons Refining furnace | 1 |
| 8 | 120 tons VD furnace | 2 |
| 9 | 12m*9m*6m Heat treatment furnace | 3 |
| 10 | 120 tons Large-scale shot blasting machine | 1 |
| 11 | 150 tons Travelling crane | 2 |
| 12 | 125 tons Travelling crane | 3 |
| 13 | 200 tons Travelling crane | 2 |
| 14 | CNC gantry boring and milling machine | 2 |
| 15 | 2.5m-10m Digital vertical lathe | 16 |
| 16 | Boring and milling machine | 13 |
| 17 | Horizontal lathe | 3 |
| 18 | Large dust removal equipment | 7 |
1)The engineer will firstly prepare the technology and do a simulation before pouring.
2)We will make a pattern of the kiln tyre based on engineer's technology.
It will cost us around one week.
After that the engineer will check the dimension and make a record.
3)Sand molding making will be made by experienced wokrers.
4)Pouring and cooling.
There are one 8tons electrical arc furnace;
Two 50 tons medium frequency furnace;
One 120 tons refining furnace and one 120 tons VD furnace;
Chemical composition
The chemical composition has a significant influence on the mechanical property and can be further affected through change of the minor alloying elements.
The scrap will be tested and stored according to the chemical composition.
There will be a record before and after pouring.
There are two direct-reading spectrometers(FOUNDRY-MASER PRO,OXFORD INSTRUMENTS) which are imported from German.
The testing equipment will be calibrated annually.
Mechanical property
Mechanical test result shows an evaluation of the metal according to customers’ requirement.
Ultrasonic test
Ultrasonic test gives an guarantee of the inside quality of the large steel castings.
A qualified UT tester will do the test with normal probe according to customers’ UT level.
The sound can detect the internal defects of the large carbon steel and alloy steel castings.
Sound waves will change according to the internal structure.During UT process,the high frequency acoustic energy is transmitted into the casting.
It travels via the casting until it hits the opposite surface,interface or defects.The interface or defects reflect portions of the energy which are collected and displayed on the test machine(the depth,width and thickness).
5)Clean the sand and cut the riser before heat treatment
6)Heat treatment will cost 7days( 4 days normalizing and 3 days tempring).
There are 8 heat treatment furances with max. one is 12m*9m*6m.
Magnetic powder inspection
It is not easy to find the tiny cracks,pores and other surface glitches on the large carbon or alloy steel castings by human eyes.In this situation,a colored dye solution is applied to the surface of the casting.
In general, dye-penetrant techniques identify defects on the surface of the casting and do not detect internal porosity or shrinkage that is not open to the surface. But it can detect rounded indications for porosity or gas on the casting surface.
Magnetic powder inspection is a quick,economic and sensitive way to find the surface defects on the large carbon or alloy steel castings.
7)dimension check and draw a line for machining.
8)Rough machining
9)NDT withe qualified inspector
10)Welding repair if needed and tempering for stress relief
11)Final machining and NDT
12)Customers' inspection and packing
Haian Haitai Casting Co.,Ltd. is established in 2003.
We supply large steel castings with low carbon or alloy steel from 3 tons to 150 tons per piece.
With a quick development,now we had supplied steel castings 6,000 tons per month.
There are three workshop for sand mold making,one workshop for machining and one for post procedure.
We have rich experience to supply castings for BOP of Russian market.
| No. | Equipment Name | Quantity(Set) |
| 1 | Sand analysis equipment | 1 |
| 2 | Impact sample low temperature meter | 1 |
| 3 | Direct reading spectrometer(OXFORD) | 2 |
| 4 | ONH analyzer | 1 |
| 5 | ZEISS metallurgical microscope | 1 |
| 6 | Pendulum impact tester | 1 |
| 7 | Microcomputer controlled electro-hydraulic servo universal test machine | 5 |
| 8 | Various hardness tester | 4 |
| 9 | Magnetic defect detector | 5 |
| 10 | Ultrasonic flaw detector(digital) | 1 |
| 11 | CX-52 Total station | 1 |
| 12 | Stylus roughness meter | 1 |
We do the test according to diffrent production step,
such as chemical composition,UT,MT and mechanical property.
In 2021,Haitai inspection and testing center got approval from CNAS.
Our company is near to Shanghai port and we can supply different packing according to customers' specification.