Multi-Press Hot Press Layout for Controlled Thermal Cycling

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Solution Overview

Problem

Conventional hot press devices are unable to achieve high strength and ductility in sheet steel through multiple heating and cooling cycles, as they lack the necessary temperature management and processing methods to effectively form high-strength components.

Innovation Solution

A hot press device configuration that includes multiple presses and a single heating furnace, allowing for repeated heating and cooling cycles with precise temperature control, using manipulators to convey the material between the furnace and presses, enabling ultra-high strength and toughness in the formed product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional hot press devices use a single heating furnace and single press configuration, then the device complexity is low, but the manufacturing precision of high-strength components cannot be achieved

Engineering Contradiction:
Improvestrength and ductility of sheet steelVSAvoidnumber of presses and heating furnaces
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The process is segmented into multiple heating and cooling cycles with distinct temperature ranges. The first heating cycle heats to a higher temperature (e.g., 950-1050°C) to form austenite, followed by cooling. The second heating cycle heats to a lower temperature (e.g., 850-950°C) for controlled cooling to achieve martensite transformation. This temporal segmentation of thermal processes enables precise microstructure control without requiring multiple simultaneous furnaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic heating and cooling cycles rather than continuous processing. The material undergoes repeated thermal cycles with controlled duration and temperature profiles. This periodic action allows the microstructure to transform in controlled stages, achieving high strength and ductility through cumulative thermal-mechanical effects.

Inventive Principle:
Principle #19Periodic action

2Strength

If multiple heating and cooling cycles are performed to achieve high strength, then the material properties improve, but the processing time increases

Engineering Contradiction:
Improveultra-high strength and toughnessVSAvoidprocessing time for multiple cycles
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The cooling phase of each cycle is designed to be continuous and efficient, transitioning the material from high-temperature austenite to room temperature as quickly as possible while maintaining control. The presses are designed with rapid cooling capabilities that continuously remove heat during the pressing phase, reducing idle time between heating and cooling stages.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent optimizes multiple parameters simultaneously: heating rate, holding time at peak temperature, cooling rate, and pressing force. By carefully adjusting these parameters, the process achieves the desired microstructure transformation in fewer cycles. The temperature ranges and cycle durations are specifically tuned to minimize processing time while ensuring complete austenite formation and subsequent martensite transformation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If precise temperature management is implemented for multiple cycles, then the material characteristics are improved, but the device complexity increases

Engineering Contradiction:
Improvetemperature control precisionVSAvoidtemperature management system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The same heating furnace and press equipment are used for both heating and cooling functions across multiple cycles. The press serves dual purposes: applying mechanical force during forming and acting as a cooling device through its mass and contact with the material. This multi-functionality reduces the need for separate dedicated heating and cooling equipment, simplifying the overall system while maintaining precise temperature control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the press itself as part of the thermal management system. The press absorbs heat from the material during the pressing operation, providing passive cooling without requiring external cooling systems. The material's own thermal mass and the press's thermal capacity work together to manage temperature transitions, reducing the complexity of active temperature control systems.

Inventive Principle:
Principle #25Self-service

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 device achieves ultra-high strength and toughness in hot-pressed components by performing multiple hot pressings with controlled thermal history, eliminating residual carbides and inducing martensite transformation, while also being more space-efficient and capable of producing components with complex shapes.

Implementation Method 1

a heating furnace 18 that heats a material Z to be pressed

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a press 12 that presses the material Z heated by the heating furnace 18

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

inducing martensite transformation

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Data Source

PatentEP3511086B1Hot press device
Publication Date: 2021.01.27 NIPPON STEEL CORPORATION
  • EP3511086B1 patent drawingFigure 1
  • EP3511086B1 patent drawingFigure 2
  • EP3511086B1 patent drawingFigure 3

AI summary

A hot press device according to the present disclosure includes a first press, a second press, a conveyance device linking the first press and the second press together, and a heating furnace provided within a conveyance range of the conveyance device.