Why steel fitting get rust and corrosion cnc machining ?

In cnc turning parts manufacture , especially our factory mainly produces OEM /ODM carbon steel pipe fitting .

We have around 70% pipe fittings is iron material , and the material is 1020,1035,1045,Q235,12L14 , 40cr , these are different type iron material.

With around 10 years cnc machine experience , cnc turnipng parts get rust and corrosion is a commom problem  Therefore today we mainly to introduce why the steel fittings get rust

and how to solve the steel fitting rust and corrosion problem .

Why the steel fittings get rust and corrosion?

Steel fittings rust and corrosion problem can be divided into three stages:

1-During production

There will different factors to cause problem , we make up as follow based on differnt reason .

• Water polishing

Water polishing detergents are usually water-based and mildly alkaline. If not rinsed and dried properly, residual moisture can cause steel fittings to rust.

•  Cutting fluid

During CNC turning, using poor-quality or low-concentration cutting fluid can cause steel parts to rust.

Some parts need several machining steps and take a long time to finish. When cutting fluid evaporates and the surface becomes dry, rust is more likely to occur.

Normally, cutting fluid can protect parts from rust for about 7–15 days, depending on the environment.

•   Season

CNC machined parts are easy to rust, especially when exposed to rain and high humidity.

During the rainy season, our factory is located near the sea, and the humid environment can accelerate the rust and corrosion of iron fittings.

In summer, our stock goods sometimes will wrapped with stretch film. If moisture inside the packaging is not noticed, water vapor can be trapped, which may cause batch rusting.

• Dust

I mention the dust because our factory is located near the mountain, so there is always a lot of dust. I think it’s important to warn people who store steel fittings in poorly maintained factories.

The factory enviroment is not suitable keep the carbon steel cnc turning parts , It is necessary to notice the dust problem . Because in the past years , when we keep finish goods after cnc machine , the goods put cover/paper can keep more than halft month mo rust .

If we keep goods expose  to air and dust , 3-5 days may get little rust . So the way to rust prevention also important .

2-After Plating / Surface Treatment

As a OEM /ODM cnc turning parts factory , we have rich experience for the differnt demand for steel fittings. It includes

1. zinc plated (blue /color /black etc) ,
2. Dacromet
3. chemical nickel plated
4. Electrophoresis
5. oil
6. nickel plated

if parts are left unpacked in normal conditions

But after you put bag and keep in good packing , it can be more than 5 years , real case we study in the warehouse . Not only oil keep in good packing can avoid rust .all these surface put in a good packing can englarge the life of rust prevention.

Real Cases of Rust Issues

Real Case: 2020 Typhoon Flood and Rust Damage

In the 2020 year typhoon season , the government not choose Reservoir flood discharge on time . The result is  machines , factories , cnc products get rust in the flood .

The Importance of Proper Packing: A Real Case of Rust in Steel Fittings

2020 we have the biggest rust problem and loss aruond 12000USD for america pipe fitting order .Because the steel fitting get rust .The packing is pipe fitting put in oil , 25pcs /cardboard ,4 cardboard total 100pcs /box and we supply this customer keep 3 years.Only this time get rust .

When we get the news , we already send 2 batch , the third batch keep in wearehouse. So we check our stock goods immediately , it also get rust after packing just 2 days . First we think the oil problem , we change a double price oil to packing again .

After 2 days goods rusted again . Finally i buy Rust-proof paper packing each pieces then solve the problem . But we still not get the reason. After around half month , we discuss with my customer ,the customer and my factory use the same box supplier . customer tell me that their brass get rust because the box . the box get problem . Then we finally know the raw material of the box have problem.The box supplier change raw material for a cheaper price and bad quality， we doubt the cardboard keep have acidic or alkaline .

So since that time all our steel fitting have 2 type packing ,

1 type ,put one plastic bag first , then use the sponge instead the carboard .

2 type , blister packing.