Water-Based Quenching Liquid Composition Suppressing Cracks

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Solution Overview

Problem

Water-based quenching liquids are prone to rapid cooling rates, leading to localized temperature differences and increased likelihood of quenching cracks in metal materials during heat treatment, which existing additives fail to adequately address.

Innovation Solution

A water-based quenching liquid composition comprising water, a linear polyalkylene glycol compound with a mass average molecular weight of 10,000 or more, and a branched polyhydric alcohol alkylene oxide adduct with a mass average molecular weight of 10,000 or more, which slows the cooling rate and reduces the risk of quenching cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water-based quenching liquid is used, then cooling performance is improved and environmental load is reduced, but cooling rate becomes too fast causing quenching cracks

Engineering Contradiction:
Improvecooling performanceVSAvoidquenching crack
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the quenching liquid by incorporating specific polymers (polyoxyalkylene derivative and maleic anhydride or its derivative) to modify the cooling rate characteristics. This parameter change allows the water-based liquid to maintain high cooling performance while reducing the harmful effect of excessive cooling speed that causes quenching cracks.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces polymer additives as intermediary substances that mediate between the coolant and the metal material. These polymers form a protective layer or modify the heat transfer characteristics, acting as a buffer that controls the cooling rate and prevents direct abrupt cooling that leads to quenching cracks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If existing quenching liquid additives are used, then some crack suppression is achieved, but cooling rate remains too fast to satisfactorily improve quenching crack

Engineering Contradiction:
Improvequenching crackVSAvoidcooling rate
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent creates a composite quenching liquid system by combining water with specific polymer additives (polyoxyalkylene derivative and maleic anhydride derivative). This composite formulation synergistically improves crack suppression while appropriately controlling the cooling rate, achieving both objectives simultaneously rather than compromising one for the other.

Inventive Principle:
Principle #40Composite materials

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 composition effectively suppresses quenching cracks by controlling the cooling rate, maintaining cooling performance even after repeated use, and enhancing safety and handling properties.

Implementation Method 1

a treatment of dipping a heated metal material in a coolant to transform into a predetermined quenched structure

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a cooling rate in a temperature region in which martensite is formed is fast, and therefore, a localized temperature difference or the like is generated in the treated material, so that crack (quenching crack) is liable to be generated

Methodology Applied
Scientific EffectThermal shock: Thermal Shock

Data Source

PatentUS11180817B2Water-based quenching liquid composition and method for manufacturing metal material using same
Publication Date: 2021.11.23 IDEMITSU KOSAN CO LTD

AI summary

Provided is a water-based quenching liquid composition which is slow in a cooling rate and is able to suppress quenching crack. The water-based quenching liquid composition is one containing water (A), a linear polyalkylene glycol compound (B), and a branched polyhydric alcohol alkylene oxide adduct (C), wherein the linear polyalkylene glycol compound (B) has a mass average molecular weight of 10,000 or more, and the branched polyhydric alcohol alkylene oxide adduct (C) is a mixed adduct of alkylene oxides having 2 to 3 carbon atoms and has a mass average molecular weight of 10,000 or more.