Al-Si Coated Hot Stamping Heating to Prevent Roller Adhesion

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Solution Overview

Problem

Existing hot stamping methods with aluminum-silicon coatings face issues of adhesion to the roller and nodulation in heat treatment furnaces, leading to reduced service life and coating integrity, particularly due to the melting of the coating during the heating process.

Innovation Solution

A three-stage heat treatment process with specific temperature and time ranges for aluminum-silicon alloy-coated steel plates, combined with a stepwise heating mode, to prevent coating adhesion and nodulation, ensuring the formation of a diffusion layer and surface alloy layer for improved coating and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional heating methods are used for aluminum-silicon alloy-coated steel plates, then heating efficiency is improved, but coating adhesion to the roller and nodulation occur

Engineering Contradiction:
Improveheating efficiencyVSAvoidcoating integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The heating process is divided into three distinct stages: first heating stage (room temperature to 600°C at 10-20°C/s), second heating stage (600°C to austenitizing temperature at 5-15°C/s), and third holding stage (austenitizing temperature hold). This segmentation prevents the coating from reaching its melting point and adhering to the roller while still achieving efficient heating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the heating rate parameters at different temperature ranges. By controlling the heating rate to be 10-20°C/s in the first stage and 5-15°C/s in the second stage, the coating temperature is kept below its melting point, preventing adhesion to the roller while maintaining heating efficiency.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If high heating rates are applied to achieve fast processing, then production cycle time is reduced, but coating melting and adhesion to the roller occur

Engineering Contradiction:
Improveproduction cycle timeVSAvoidcoating adhesion and nodulation
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The heating process is segmented into three stages with different heating rates. The first stage uses a higher rate (10-20°C/s) for rapid initial heating, while the second stage uses a controlled rate (5-15°C/s) to avoid coating melting. This segmentation reduces overall production cycle time while preventing coating adhesion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies preliminary anti-action by controlling the heating rate before the coating reaches its melting temperature. The third holding stage at austenitizing temperature ensures the coating is properly prepared before stamping, preventing subsequent adhesion and nodulation issues.

Inventive Principle:
Principle #9Preliminary anti-action

3Strength

If the coating is heated to high temperatures for austenitizing, then the mechanical properties of the steel are improved, but the coating adheres to the roller and nodulation occurs

Engineering Contradiction:
Improvemechanical properties of steelVSAvoidcoating integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention applies local quality by treating the coating and substrate differently during heating. The substrate is heated to austenitizing temperature to improve mechanical properties, while the coating is protected from melting through controlled heating rates. The diffusion layer formation creates a gradient structure that maintains coating integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes temperature parameters through three stages: first heating (room temperature to 600°C), second heating (600°C to austenitizing temperature), and third holding (austenitizing temperature hold). This parameter control ensures the substrate achieves the desired mechanical properties while the coating remains intact and does not adhere to the roller.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If conventional single-stage heating is used, then the process is simple, but coating adhesion and nodulation reduce roller service life

Engineering Contradiction:
Improveheating process complexityVSAvoidroller service life
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The heating process is segmented into three stages with specific temperature ranges and heating rates. This segmentation prevents coating adhesion and nodulation, thereby extending roller service life. The increased process complexity is justified by the significant improvement in roller durability and coating integrity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively reduces adhesion and nodulation, extends the service life of heat treatment furnace rollers, maintains coating integrity, and enhances the mechanical and welding performance of hot stamping components.

Implementation Method 1

the heat treatment process of the blank comprises a first heating and holding stage, a second heating and holding stage, and a third heating and holding stage

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

conducting heat treatment and hot stamping of the blank; wherein, in the heat treatment of the blank, the blank is put into a heat treatment furnace for austenitizing heat treatment

Methodology Applied
Scientific EffectAustenitizing: Phase Change

Data Source

PatentEP3770295B1Manufacturing method for hot stamping component having aluminium-silicon alloy coating
Publication Date: 2023.08.16 BAOSHAN IRON & STEEL CO LTD
  • EP3770295B1 patent drawingFigure 1~2
  • EP3770295B1 patent drawingFigure 3~4
  • EP3770295B1 patent drawingFigure 5~6

AI summary

A manufacturing method for a hot stamping component having an aluminium-silicon alloy coating, and a hot stamping component, said method comprising the following steps: a steel plate coated with an aluminium-silicon alloy coating is machined into a blank having a shape required for a part, and the blank is subjected to heat treatment and hot stamping. The blank heat treatment is two-stage or three-stage heating, and the temperature of the heating increases in steps. The steel plate coated with the aluminium-silicon alloy coating comprises a substrate, and the aluminium-silicon alloy coating on at least one surface of the substrate. The present method fully takes into account the characteristics of the aluminium-silicon coating, effectively solves the problem of aluminium-silicon coating roller adhesion, reduces the probability of heat treatment furnace roller nodulation, increases roller service life, and also ensures the integrity of the hot stamping component coating, and the mechanical properties, welding performance, coating performance and corrosion resistance of the component.