The car giant started by marrying the daughter of the king

Chapter 116 Dacromet, a legend in surface treatment
The automotive industry is much more complex than many people imagine.

Especially with the strengthening of specialized division of labor, the importance of the industrial chain has become increasingly higher.

In later generations, due to the popularity of concepts such as "zero inventory", if any of the suppliers of each OEM had problems with parts supply, the OEM would have to shut down production.

When the main engine manufacturers shut down their production lines, those large supporting factories, such as seat factories, exhaust pipe factories, door panel factories and other parts manufacturers, basically had to stop production as well.

If the suspension lasts a few more days, 80% of the manufacturers in the entire industry chain will have to suspend production.

Otherwise, the produced parts would immediately fill up the warehouse, and there would not even be enough trolleys to load the parts.

So no matter what part it is, its importance is not low.

Not to mention important security parts related to safety performance such as wheel bolts.

"Liao Ke, what surface treatment process does Chaoyang Fastener Factory currently use to process wheel bolts?"

It is definitely difficult to make any decision before you understand the situation clearly.

Jiang Hui felt that the Chaoyang Fastener Factory's surface treatment technology was most likely not up to par, which was why the corrosion resistance test failed to meet the requirements of the drawings.

Although he did not draw this blueprint himself, he was the one who specifically instructed on the technical requirements for corrosion resistance.

What Liao Chengwen wants to modify now is probably the surface treatment requirements.

"Electrogalvanizing. Most bolts are now rust-proofed by electrogalvanizing or hot-dip galvanizing."

"This is also a method with relatively low cost and relatively mature technology."

Liao Chengwen must be familiar with common surface treatment technologies.

After all, he is the head of the technical department.

“Are there any obvious problems with their electrogalvanizing production line?”

Electrogalvanizing is a relatively traditional surface treatment technology. If it is handled well, the anti-corrosion effect is actually quite good.

Of course, this technology is definitely not the best surface treatment technology for corrosion resistance.

"Pre-treatment of electroplating is the basis for electrogalvanizing and the key to ensuring product quality."

"Today I went to Chaoyang Fastener Factory to confirm whether the plated substrate was treated to the specified requirements before electroplating."

"After all, even if there is a good electroplating solution, appropriate electroplating parameters, good equipment for controlling electroplating parameters, and highly skilled personnel, it is impossible to obtain an electroplated layer that meets quality requirements if the pre-treatment is not done well."

"But I have confirmed that Chaoyang Fastener Factory has done a very good job in this regard, and there are no problems with the process."

Liao Chengwen gave his own judgment very affirmatively.

Before electrogalvanizing, the most basic requirement is to remove grease on the base metal and foreign matter that affects the adhesion of the coating and other quality requirements, and to remove surface oxides so that the surface of the wheel bolts has a specified cleanliness and a certain activity to ensure a firm bond between the coating and the base.

In most cases, there is no problem in this link and electrogalvanizing is not prone to problems.

No matter what we do now, there is no way to meet the corrosion resistance requirements specified in the drawings. Liao Chengwen thinks there must be something wrong with the requirements of the drawings.

“Has the process control of the electroplating process also been confirmed to be problem-free?”

Jiang Hui didn't distrust Liao Chengwen, but he wanted to confirm the situation before making the next arrangements. "No problem, their process flow is very clear, each process has clear electroplating parameters, the concentration of the electroplating solution is also controlled, and the workers are operating according to the regulations."

"There shouldn't be any problems with the wheel bolts produced under these circumstances."

Liao Chengwen once again emphasized that there was no problem with the Chaoyang Fastener Factory.

There is no problem with the supporting factory, but the parts produced do not meet the corrosion resistance requirements on the drawings, so there must be something wrong with the drawings.

Jiang Hui naturally got the implication of Liao Chengwen's words.

"How many hours of salt spray testing did it take for white rust to appear?"

"About 120% white rust appeared after about 10 hours, and slight red rust appeared after 240 hours."

"This test result is actually not bad, and is even slightly better than the corrosion resistance of the wheel bolts on the current BJ212."

"Your requirement of no red rust for 960 hours is something that no domestic manufacturer can achieve."

Liao Chengwen gave his opinion with certainty.

In this era, the most common surface treatments used on various Chinese auto parts are electroplating and painting.

No matter which one it is, it is far from meeting Jiang Hui's requirements.

Not to mention 960 hours of salt spray testing without red rust, even 480 hours without red rust is impossible.

It is conceivable how outrageous the request made by Jiang Hui seemed to Liao Chengwen!

Not to mention car parts, even the various bolts on military products such as tanks and artillery do not have corrosion resistance requirements that meet the level that Jiang Hui mentioned.

"The previous drawings specified various requirements for surface treatment. As for the surface treatment process, it was marked as electrogalvanizing or other surface treatment technologies of the same technical level. It is estimated that in addition to electrogalvanizing, no one tried other surface treatment processes to see if they could meet the requirements of the drawings."

"I accidentally saw a document saying that a surface treatment technology expert in the United States developed a highly dispersed water-soluble coating that is mainly made of metal zinc flakes, with aluminum flakes, chromic acid, and deionized water as solvents."

"This coating is applied to the metal substrate and then baked in a fully closed-loop cycle to form a thin coating, which they call Dacromet coating."

"This coating can significantly improve the corrosion resistance requirements and overcome the short corrosion life of traditional processes."

"I think Chaoyang Fastener Factory can consider using Dacromet surface treatment technology to produce wheel bolts, and even some other bolts and nuts can also adopt this process."

After hearing what Jiang Hui said, Liao Chengwen couldn't help but frown.

If other college students who had just graduated a few months ago proposed new surface treatment solutions to him, he would definitely not even want to listen and would just turn around and leave.

But Jiang Hui spoke very convincingly, even using difficult-to-pronounce terms like "Dacromet surface treatment", which is obviously an advanced foreign surface treatment technology. He could not afford to underestimate it.

"Xiao Jiang, can this Dacromet surface treatment process really prevent the wheel bolts from rusting after a 960-hour salt spray test?"

Although it is just an inconspicuous surface treatment technology, if it can really achieve the effect that Jiang Hui said, it will definitely be of extraordinary significance.

Liao Chengwen obviously also realizes this.

(End of this chapter)