PRESSLER® ZINC COATING HOT STAMPING TECHNOLOGY

1.Current Issues in Hot Forming (HF) & Motivation

2.Pressler Zinc Coating HF Technology

3.Pressler Zinc Coating HF Performance

4.Next Steps

5.Summary

Current Issues in Hot Forming (HF) & Motivation  

Current Issue 1: Poor Anti-Corrosion on Al-Si Coated Parts

Statement: Al-Si coated hot stamping parts have poor corrosion resistance on both cosmetic and perforating. Corrosions start at weld line, surface scratch from forming, trim edge, and any area not covered by E-coating.

Al-Si COATED B-PILLAR	AFTER 48H NEUTRUAL SALT SPRAY (NSS)	TAILOR B-PILLAR AFTER 16H NSS	AFTER 240H NSS

Current Issue2：Low Bending Angle of Al-Si Coated Parts

Statement: Al-Si coated hot stamping parts have low bending angles

SEM of Al-Si coating after hot stamping (500 times)	Carbon content distribution

Table 1 Bending angles of AL-Si coated 22MnB5 plates.“patent：CN 108588612A”

Coating types	Thickness	Coating thickness	Bending Angle 1	Bending Angle 2	Average
Al-Si	1.5mm	30-50um	50.8°	52.7°	51.8°

OXIDE SCALE (>5um)

Current Issue 3: High Cost on Al-Si Coated TWB

Statement: ： Al-Si coating needs to be removed before welding

SEM of section of TWB of Al-Si coated blank  Picture from VW TL4225

It is generally not allowed to appear brittle fe - Al phase in the weld line of al - Si pre - coated laser butt welding parts

Current Issue 4: Shorten Life of Furnace Rollers on Al- Si heating

Statement: Melting Al-Si coating during heating will damage the surface of ceramic rollers. 

Contamination of ceramic roller by melting Ai-Si coating

Under high temperature, the coating melts and continuously diffuses inside  the ceramic roller, leading to the hump formation or even fracture of the ceramic rollers.  Therefore it reduces the service life of the rollers

Main Issues in Al-Si Coating and Zinc Coating Indirect PHS Parts

Al-Si Coating PHS Parts		Zinc (Zn) Coating Indirect PHS Parts
Poor corrosion resistance capability		Crack in coating layer or even in substrate
Poor bending angles		Shot blasting needed to remove Zinc Oxide (ZnO)
High cost on TWB		High cost on Indirect PHS
Liquid Al-Si contamination on furnace roller		Vapor or liquid Zinc contamination on furnace

Pressler Vacuum Hot Forming Zinc-Coated Parts

Manufacturing Process :

Laser Blanking		Vacuum heating		Hot forming
Product		Electro-Galvanizing		Laser cutting

Pressler Third-Generation Hot Stamping Technology

Heating Process:

Pressler Vacuum Heating Hot Forming Try-Out Line

Vacuum Heating Hot Forming: Oxide Layer

OXIDE LAYER THICKNESS< 2μm

Zinc Coating Uniformity

电镀锌挂架

The coating tolerance range of the electroplating process is 7-13um

Three-Point Bending Angle of Zinc Coated Parts

Coating Type	Material Thickness	Coating Thickness	Bending Angle 1	Bending Angle 1	Bending Angle 1	Bending Angle 1	Bending Angle 2	Bending Angle 3
Electro-galvanized Plate	1.5mm	7-13um	80.65°	81.77°	76.44°	81.21°	76.11°	67.6°

TEST EQUIPMENT	3-POINT BENDING ANGLE SAMPLE	DROP TOWER TEST

Cyclic Corrosion Resistance Performance

Testing Standard: AA-0224:2018 Cyclic Corrosion Test, DIN EN ISO 11997-1, Cycle B

氢含量测试报告

Tab1. Diffusive  hydrogen contents  in heat treated  (A1) and  non-heat treated samples (A2)both in electro galvanized and depleted conditions.

Heat treated A1	Galvanized samples [ppm]	Average [ppm]	Deplated samples [ppm]	Average [ppm]
A1-1	0.29	0.33 士 0.04
A1-2	0.37
A1-3			0.08	0.08 主 0.005
A1-4			0.08
A1-5			0.07
Non.heat treated A2	Galvanized samples [ppm]	Average [ppm]	Deplated samples [ppm]	Average [ppm]
A2-1	11.62	13.17 士 1.55
A2-2	14.71
A2-3			0.24
A2-4			0.16

80th materials were analyzed after deplation as well as in the as-delivered galvanized condition. Deplating was performed in 18.5% HCI + 5 g/ l Hexamethylenetetramine  (cor­ rosion inhibitor). AII analyses were carried out by means of Thermal Desorption Spectroscopy  (TDS) at an isothermal temperature of 300 oC.

Hydrogen Embrittlement Test

U-Bend Specimen U 型折弯样品

(SEP 1970)

Low Cost and Advantages

Low Cost Factors ：

Uncoated 22MnB5 material = lower cost

TWB of uncoated blank = lower cost

  Vacuum heating = same cost as Atmosphere Protection Heating

Zinc Plating and Tempering = same cost as Al-Si coating

Advantages：

 Common tailor welding

Pressler Summary

Pressler technology on hot stamping parts provides automotive OEMs a
new solution on reducing cost and enhancing corrosion resistance