Cast ZG25CrNiMo Annular Petroleum Machinery Castings

1)Pattern making

We have our own wooden pattern making workshop.
But our company is always busy,
we also have around 10 sub-contractors for pattern making.
They help us for the pattern but will be inspected according to our rules.
We will record for every pattern inspection.

2)Silica or chorme sand cores

The area for sand mold core making is 8000 m2.

The biggest hollow pit is 87m*16m*(-3.5m)

The deepest pit is 45m*16m*(-6m)

3)Melting and PouringWe always do the melting after mid-night for cheaper electric charge.

And we normally do pouring in the early morning.

4)Machining

We have 3.5 to 10m vertical lathes.

We have 10 sets milling and boring machines.

5)NDT test

1)The engineer will firstly prepare the technology and do a simulation before pouring.

2)Pattern making

we make the pattern by ourself.

If the quantity for same castings is more than 10pcs,the pattern will be free.

3)Sand molding making will be made by experienced wokrers.

Most of them have more than 10 years' experience.

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;

The max. melting weight can be around 200 tons,

the unti weight we can make is 150 tons after finished machining.

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.

5)Clean the sand and cut the riser after normalizing by hot cutting method.

6)Heat treatment will cost 7 days( 4 days normalizing and 3 days tempring).

There are 8 heat treatment furances with max. one is 12m*9m*6m.

7)dimension check and draw a line for machining.

VT inspection after we take the casting out from the sand,

the inspection team will also check the machining allowance.

8)Rough machining

After rough machining,the surface will be ok for NDT.

We can firstly check the quality and continue the next procedure.

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.

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.