Tecniche di lavorazione del vetro di Murano – Una guida completa
La procedura prevede l'aggiunta di diversi ossidi metallici alla composizione del vetro riscaldato, come ferro e rame, che produrranno metallo microscopico. le ...
known as annealing
The completed product is stored in a chilling furnace known as a "tempera" where it gently cools.This is <anchor>known as annealing</anchor>, guaranteeing that glass does not break due to internalstresses or excessive temperature changes. On that note, let's look at some of the most famous Murano Glassmaking techniques.
What is Annealing? A Complete Process Guide - TWI
What is Annealing? A Complete Process Guide - TWI



Subscribe to our newsletter to receive the latest news and events from TWI:

[Subscribe >](/account/newsletter-preferences?s=popup)

[Skip to content](#main)

[Home](/)

- [Who we are](/who-we-are)
- [What we do](/what-we-do)
- [Media and events](/media-and-events)
- Technical knowledge
- [Careers](/careers)
- [Engineering Jobs](/theweldinginstitute-jobs)
- [Contact us](/contact)

- [Go to Who we are](/who-we-are)
- [Industrial Membership](/who-we-are/industrial-membership)
- [Professional Membership](/who-we-are/professional-membership)
- [Our Members](/who-we-are/our-members)
- Who We Work With
- [Executive Team](/who-we-are/executive-team)
- Ethos and Values
- [Technology Fellows](/who-we-are/technology-fellows)
- [Meet the Experts](/who-we-are/meet-the-experts)
- Innovation
- Corporate Governance
- [Innovation Timeline](/who-we-are/innovation-timeline)
- [Diversity and Inclusion](/who-we-are/ethos-and-values/diversity-and-inclusion)

- Strategic Programmes
- Industry Sectors
- [Suppliers](/who-we-are/who-we-work-with/suppliers)
- [Member Showcase](/who-we-are/who-we-work-with/members-showcase)

- [Support for SMEs](/who-we-are/who-we-work-with/strategic-programmes/support-for-smes)

- [Aerospace](/who-we-are/who-we-work-with/industry-sectors/aerospace)
- [Automotive](/who-we-are/who-we-work-with/industry-sectors/automotive)
- [Defence](/who-we-are/who-we-work-with/industry-sectors/defence)
- [Engineering and Fabrication](/who-we-are/who-we-work-with/industry-sectors/engineering-and-fabrication)
- [Marine](/who-we-are/who-we-work-with/industry-sectors/marine)
- [Medical Equipment and Healthcare](/who-we-are/who-we-work-with/industry-sectors/medical-equipment)
- [Oil and Gas](/who-we-are/who-we-work-with/industry-sectors/oil-and-gas)
- [Power](/who-we-are/who-we-work-with/industry-sectors/power)
- [Rail](/who-we-are/who-we-work-with/industry-sectors/rail)
- [Electronics and Sensors](/who-we-are/who-we-work-with/industry-sectors/electronics-and-sensors)

- [Go to Ethos and Values](/who-we-are/ethos-and-values)
- [Ethics and Integrity](/who-we-are/ethos-and-values/Ethics-and-Integrity)
- [Modern Slavery Statement](/who-we-are/ethos-and-values/modern-slavery-statement)
- [Code of Conduct](/who-we-are/ethos-and-values/Code-of-Conduct)
- [Safeguarding Policy](/who-we-are/ethos-and-values/safeguarding-policy)
- [Prevent Policy](/who-we-are/ethos-and-values/prevent-policy)
- [Gender Pay Report](/who-we-are/ethos-and-values/gender-pay-report)
- [Diversity and Inclusion](/who-we-are/ethos-and-values/diversity-and-inclusion)
- [Values Recognition Scheme](/who-we-are/ethos-and-values/Values-Recognition-Scheme)

- [Structural Integrity Research Foundation](/who-we-are/innovation/structural-integrity-research-foundation)
- [TWI Innovation Network](/who-we-are/innovation/twi-innovation-network)
- [National Structural Integrity Research Centre](/who-we-are/innovation/national-structural-integrity-research-centre)

- [TWI Group](/who-we-are/corporate-governance/twi-group)
- [Report and Accounts](/who-we-are/corporate-governance/reports-and-accounts)
- [Corporate Social Responsibility](/who-we-are/corporate-governance/corporate-social-responsibility)
- [Quality, Safety and Environment](/who-we-are/corporate-governance/quality-safety-and-environment)
- [Procurement](/who-we-are/corporate-governance/procurement)

- [Go to What we do](/what-we-do)
- Research and Technology
- [Public Funded Projects](/what-we-do/research-and-technology/research-programmes/public-funded-projects)
- Services and Support
- [Training Courses](/what-we-do/training-courses)
- Digital Strategy
- [Trending Topics](/what-we-do/trending-topics)
- [Our Processes](/what-we-do/our-processes)
- [A to Z](/what-we-do/a-z)
- [FAQs](/technical-knowledge/faqs)

- Research Programmes
- Technologies
- [Equipment Directory](/what-we-do/research-and-technology/equipment-directory)

- Core Research Programme
- [Joint Industry Projects](/what-we-do/research-and-technology/research-programmes/joint-industry-projects)

- [Industrial Member Reports](/what-we-do/research-and-technology/research-programmes/core-research-programme/industrial-member-reports)
- [Report Abstracts](/what-we-do/research-and-technology/research-programmes/core-research-programme/report-abstracts)
- [Executive Summaries](/what-we-do/research-and-technology/research-programmes/core-research-programme/executive-summaries)
- [Technical Literature Reviews](/what-we-do/research-and-technology/research-programmes/core-research-programme/technical-literature-reviews)
- [Governance](/what-we-do/research-and-technology/research-programmes/core-research-programme/governance)
- [CRP Media and Events](/what-we-do/research-and-technology/research-programmes/core-research-programme/crp-media-and-events)

- [Additive Manufacturing](/what-we-do/research-and-technology/technologies/additive-manufacturing)
- [Big Data and Sensors](/what-we-do/research-and-technology/technologies/big-data-and-sensors)
- [Coating and Surface Engineering](/what-we-do/research-and-technology/technologies/coating-and-surface-engineering)
- [Electrification](/what-we-do/research-and-technology/technologies/electrification)
- [Industry 4.0](/what-we-do/research-and-technology/technologies/industry-4-0)
- [Inspection and Testing](/what-we-do/research-and-technology/technologies/materials-testing-and-inspection)
- [Welding, Joining and Cutting](/what-we-do/research-and-technology/technologies/welding-joining-and-cutting)

- Technical Support
- Product and Process Development
- Technology Acquisition
- [Engineering Consultancy](/what-we-do/engineering-consultancy)
- Manufacturing and Production Support
- Asset Management
- Failure Analysis and Repair

- [Codes and Standards](/what-we-do/services-and-support/technical-support/codes-and-standards)
- [Training Courses](/what-we-do/training-courses)
- [Certification Schemes](/what-we-do/services-and-support/technical-support/certification-schemes)
- [Welding Engineering](/what-we-do/services-and-support/technical-support/welding-engineering)

- [Design for Manufacture/Inspection](/what-we-do/services-and-support/product-process-development/design-for-manufacture-inspection)
- [Material/Product Testing](/what-we-do/services-and-support/product-process-development/material-product-testing)
- [Process Modelling/Simulation](/what-we-do/services-and-support/product-process-development/process-modelling-simulation)
- [Prototyping](/what-we-do/services-and-support/product-process-development/prototyping)

- [Procedure Development](/what-we-do/services-and-support/technology-acquisition/procedure-development)
- Procedure Qualification
- [Process Feasibility Study](/what-we-do/services-and-support/technology-acquisition/process-feasibility-study)
- [System Specification](/what-we-do/services-and-support/technology-acquisition/system-specification)
- [Commissioning](/what-we-do/services-and-support/technology-acquisition/commissioning)

- [Software Products](/what-we-do/services-and-support/technology-acquisition/procedure-qualification/software-products)

- [Process Procedure Review](/what-we-do/services-and-support/manufacturing-production-support/process-procedure-review)
- [Site Audits and Certification](/what-we-do/services-and-support/manufacturing-production-support/site-audits-and-certification)
- [Troubleshooting](/what-we-do/services-and-support/manufacturing-production-support/troubleshooting)

- [Condition/Structural Health Monitoring](/what-we-do/services-and-support/asset-management/condition-and-structural-health-monitoring)
- Fitness for Service
- [Inspection and Testing](/what-we-do/services-and-support/asset-management/inspection-and-testing-services)
- [Decommisioning](/what-we-do/services-and-support/asset-management/decommissioning)

- [Software Products](/what-we-do/services-and-support/asset-management/fitness-for-service/software-products-fitness-for-service)

- [Failure Investigation](/what-we-do/services-and-support/failure-analysis-and-repair/failure-investigation)
- [Repair Procedure Development](/what-we-do/services-and-support/failure-analysis-and-repair/repair-procedure-development)
- [Dispute/Litigation Support](/what-we-do/services-and-support/failure-analysis-and-repair/dispute-litigation-support)

- [Automation](/what-we-do/digital-strategy/automation)
- [Connectivity](/what-we-do/digital-strategy/connectivity)
- [Data Science](/what-we-do/digital-strategy/data-science)
- [Modelling and Simulation](/what-we-do/digital-strategy/modelling-and-simulation)
- [Software Development](/what-we-do/digital-strategy/software-development)

- [Go to Media and events](/media-and-events)
- [Events Diary](/media-and-events/events-diary/all-events)
- [Press Releases](/media-and-events/press-releases)
- [Insights](/media-and-events/insights)
- [Our Stories](/media-and-events/our-stories)
- [Our Podcast](/media-and-events/science-and-engineering-podcasts)

- [Go to Technical knowledge](/technical-knowledge)
- Search


- [Go to Careers](/careers)
- [Current Vacancies](/careers/current-vacancies)
- Career Options
- Life at TWI
- [Our People](/careers/our-people)

- [Administrative and Customer Services](/careers/career-options/administrative-and-customer-services)
- [Apprenticeships](/careers/career-options/apprenticeships)
- [Corporate and Business Support](/careers/career-options/corporate-and-business-support)
- [Engineering Technicians](/careers/career-options/engineering-technicians)
- [Engineering, Researchers and Scientists](/careers/career-options/engineering-researchers-and-scientists)
- [Internships and Industrial Placements](/careers/career-options/internships-and-industrial-placements)
- [Marketing and Business Development](/careers/career-options/marketing-and-business-development)
- [Postgraduate](/careers/career-options/postgraduate)
- [Training and Examinations](/careers/career-options/training-and-examinations)

- [Benefits](/careers/life-at-twi/benefits)

- [Go to Contact us](/contact)
- [Caspian Sea](/locations/caspian-sea/contact "Contact Us - Caspian Sea")
- [China](/locations/south-east-asia/contact-us.aspx#China "Contact Us - China")
- [India and Bangladesh](/locations/india/contact "Contact Us - India and Bangladesh")
- [Japan and South Korea](/contact/twi-addresses/east-asia "Contact Us - Japan and South Korea")
- [Mainland Europe and Turkey](/contact/twi-addresses/mainland-europe "Contact Us - Mainland Europe and Turkey")
- [Middle East, Africa and Pakistan](/locations/middle-east/contact "Contact Us - Middle East, Africa and Pakistan")
- [South East Asia and Australia](/locations/south-east-asia/contact-us "Contact Us - South East Asia and Australia")
- [United Kingdom](/contact/find-us "Contact Us - United Kingdom")

- Login


[Login](/account/login)



[Logout](/account/login?logout=true)



[Register](/account/register)



[Members' Portal](/portal)

- Global sites


- [Caspian Sea](https://www.twi-global.com/locations/caspian-sea/home.aspx)
- [China](https://www.twi-global.com/locations/china/home.aspx)
- [Germany](https://www.twi-global.com/locations/deutschland/home.aspx)
- [Greece](https://www.twi-hellas.com)
- [India](https://www.twi-global.com/locations/india/home.aspx)
- [Japan](http://www.twijapan.jp)
- [Middle East](https://www.twi-global.com/locations/middle-east/home.aspx)
- [Pakistan](https://www.twi-global.com/locations/pakistan/home.aspx)
- [Romania](https://www.twi-global.com/locations/romania/home.aspx)
- [South East Asia](https://www.twi-global.com/locations/south-east-asia/home.aspx)

- [Facebook](http://www.facebook.com/twiltd)
- [Twitter](https://twitter.com/twi_ltd)
- [LinkedIn](http://www.linkedin.com/groups?mostPopular=&gid=2888580)
- [YouTube](http://www.youtube.com/twiltd)
- [Instagram](https://www.instagram.com/twi_ltd/)

- Login


[Login](/account/login)



[Logout](/account/login?logout=true)



[Register](/account/register)



[Members' Portal](/portal)

- Global sites


- [Caspian Sea](https://www.twi-global.com/locations/caspian-sea/home.aspx)
- [China](https://www.twi-global.com/locations/china/home.aspx)
- [Germany](https://www.twi-global.com/locations/deutschland/home.aspx)
- [Greece](https://www.twi-hellas.com)
- [India](https://www.twi-global.com/locations/india/home.aspx)
- [Japan](http://www.twijapan.jp)
- [Middle East](https://www.twi-global.com/locations/middle-east/home.aspx)
- [Pakistan](https://www.twi-global.com/locations/pakistan/home.aspx)
- [Romania](https://www.twi-global.com/locations/romania/home.aspx)
- [South East Asia](https://www.twi-global.com/locations/south-east-asia/home.aspx)

- [Who we are](/who-we-are)  - [Industrial Membership](/who-we-are/industrial-membership)
  - [Professional Membership](/who-we-are/professional-membership)
  - [Our Members](/who-we-are/our-members)
  - [Who We Work With](/who-we-are/who-we-work-with)  - [Strategic Programmes](/who-we-are/who-we-work-with/strategic-programmes)    - [Support for SMEs](/who-we-are/who-we-work-with/strategic-programmes/support-for-smes)
  - [Industry Sectors](/who-we-are/who-we-work-with/industry-sectors)    - [Aerospace](/who-we-are/who-we-work-with/industry-sectors/aerospace)
    - [Automotive](/who-we-are/who-we-work-with/industry-sectors/automotive)
    - [Defence](/who-we-are/who-we-work-with/industry-sectors/defence)
    - [Engineering and Fabrication](/who-we-are/who-we-work-with/industry-sectors/engineering-and-fabrication)
    - [Marine](/who-we-are/who-we-work-with/industry-sectors/marine)
    - [Medical Equipment and Healthcare](/who-we-are/who-we-work-with/industry-sectors/medical-equipment)
    - [Oil and Gas](/who-we-are/who-we-work-with/industry-sectors/oil-and-gas)
    - [Power](/who-we-are/who-we-work-with/industry-sectors/power)
    - [Rail](/who-we-are/who-we-work-with/industry-sectors/rail)
    - [Electronics and Sensors](/who-we-are/who-we-work-with/industry-sectors/electronics-and-sensors)
  - [Suppliers](/who-we-are/who-we-work-with/suppliers)
  - [Member Showcase](/who-we-are/who-we-work-with/members-showcase)
  - [Executive Team](/who-we-are/executive-team)
  - [Ethos and Values](/who-we-are/ethos-and-values)  - [Ethics and Integrity](/who-we-are/ethos-and-values/Ethics-and-Integrity)
  - [Modern Slavery Statement](/who-we-are/ethos-and-values/modern-slavery-statement)
  - [Code of Conduct](/who-we-are/ethos-and-values/Code-of-Conduct)
  - [Safeguarding Policy](/who-we-are/ethos-and-values/safeguarding-policy)
  - [Prevent Policy](/who-we-are/ethos-and-values/prevent-policy)
  - [Gender Pay Report](/who-we-are/ethos-and-values/gender-pay-report)
  - [Diversity and Inclusion](/who-we-are/ethos-and-values/diversity-and-inclusion)
  - [Values Recognition Scheme](/who-we-are/ethos-and-values/Values-Recognition-Scheme)
  - [Technology Fellows](/who-we-are/technology-fellows)
  - [Meet the Experts](/who-we-are/meet-the-experts)
  - [Innovation](/who-we-are/innovation)  - [Structural Integrity Research Foundation](/who-we-are/innovation/structural-integrity-research-foundation)
  - [TWI Innovation Network](/who-we-are/innovation/twi-innovation-network)
  - [National Structural Integrity Research Centre](/who-we-are/innovation/national-structural-integrity-research-centre)
  - [Corporate Governance](/who-we-are/corporate-governance)  - [TWI Group](/who-we-are/corporate-governance/twi-group)
  - [Report and Accounts](/who-we-are/corporate-governance/reports-and-accounts)
  - [Corporate Social Responsibility](/who-we-are/corporate-governance/corporate-social-responsibility)
  - [Quality, Safety and Environment](/who-we-are/corporate-governance/quality-safety-and-environment)
  - [Procurement](/who-we-are/corporate-governance/procurement)
  - [Innovation Timeline](/who-we-are/innovation-timeline)
  - [Diversity and Inclusion](/who-we-are/ethos-and-values/diversity-and-inclusion)
- [What we do](/what-we-do)  - [Research and Technology](/what-we-do/research-and-technology)
  - [Research Programmes](/what-we-do/research-and-technology/research-programmes)    - [Core Research Programme](/what-we-do/research-and-technology/research-programmes/core-research-programme)      - [Industrial Member Reports](/what-we-do/research-and-technology/research-programmes/core-research-programme/industrial-member-reports)
      - [Report Abstracts](/what-we-do/research-and-technology/research-programmes/core-research-programme/report-abstracts)
      - [Executive Summaries](/what-we-do/research-and-technology/research-programmes/core-research-programme/executive-summaries)
      - [Technical Literature Reviews](/what-we-do/research-and-technology/research-programmes/core-research-programme/technical-literature-reviews)
      - [Governance](/what-we-do/research-and-technology/research-programmes/core-research-programme/governance)
      - [CRP Media and Events](/what-we-do/research-and-technology/research-programmes/core-research-programme/crp-media-and-events)
    - [Joint Industry Projects](/what-we-do/research-and-technology/research-programmes/joint-industry-projects)
  - [Technologies](/what-we-do/research-and-technology/technologies)    - [Additive Manufacturing](/what-we-do/research-and-technology/technologies/additive-manufacturing)
    - [Big Data and Sensors](/what-we-do/research-and-technology/technologies/big-data-and-sensors)
    - [Coating and Surface Engineering](/what-we-do/research-and-technology/technologies/coating-and-surface-engineering)
    - [Electrification](/what-we-do/research-and-technology/technologies/electrification)
    - [Industry 4.0](/what-we-do/research-and-technology/technologies/industry-4-0)
    - [Inspection and Testing](/what-we-do/research-and-technology/technologies/materials-testing-and-inspection)
    - [Welding, Joining and Cutting](/what-we-do/research-and-technology/technologies/welding-joining-and-cutting)
  - [Equipment Directory](/what-we-do/research-and-technology/equipment-directory)
  - [Public Funded Projects](/what-we-do/research-and-technology/research-programmes/public-funded-projects)
  - [Services and Support](/what-we-do/services-and-support)  - [Technical Support](/what-we-do/services-and-support/technical-support)    - [Codes and Standards](/what-we-do/services-and-support/technical-support/codes-and-standards)
    - [Training Courses](/what-we-do/training-courses)
    - [Certification Schemes](/what-we-do/services-and-support/technical-support/certification-schemes)
    - [Welding Engineering](/what-we-do/services-and-support/technical-support/welding-engineering)
  - [Product and Process Development](/what-we-do/services-and-support/product-process-development)    - [Design for Manufacture/Inspection](/what-we-do/services-and-support/product-process-development/design-for-manufacture-inspection)
    - [Material/Product Testing](/what-we-do/services-and-support/product-process-development/material-product-testing)
    - [Process Modelling/Simulation](/what-we-do/services-and-support/product-process-development/process-modelling-simulation)
    - [Prototyping](/what-we-do/services-and-support/product-process-development/prototyping)
  - [Technology Acquisition](/what-we-do/services-and-support/technology-acquisition)    - [Procedure Development](/what-we-do/services-and-support/technology-acquisition/procedure-development)
    - [Procedure Qualification](/what-we-do/services-and-support/technology-acquisition/procedure-qualification)      - [Software Products](/what-we-do/services-and-support/technology-acquisition/procedure-qualification/software-products)
    - [Process Feasibility Study](/what-we-do/services-and-support/technology-acquisition/process-feasibility-study)
    - [System Specification](/what-we-do/services-and-support/technology-acquisition/system-specification)
    - [Commissioning](/what-we-do/services-and-support/technology-acquisition/commissioning)
  - [Engineering Consultancy](/what-we-do/engineering-consultancy)
  - [Manufacturing and Production Support](/what-we-do/services-and-support/manufacturing-production-support)    - [Process Procedure Review](/what-we-do/services-and-support/manufacturing-production-support/process-procedure-review)
    - [Site Audits and Certification](/what-we-do/services-and-support/manufacturing-production-support/site-audits-and-certification)
    - [Troubleshooting](/what-we-do/services-and-support/manufacturing-production-support/troubleshooting)
  - [Asset Management](/what-we-do/services-and-support/asset-management)    - [Condition/Structural Health Monitoring](/what-we-do/services-and-support/asset-management/condition-and-structural-health-monitoring)
    - [Fitness for Service](/what-we-do/services-and-support/asset-management/fitness-for-service)      - [Software Products](/what-we-do/services-and-support/asset-management/fitness-for-service/software-products-fitness-for-service)
    - [Inspection and Testing](/what-we-do/services-and-support/asset-management/inspection-and-testing-services)
    - [Decommisioning](/what-we-do/services-and-support/asset-management/decommissioning)
  - [Failure Analysis and Repair](/what-we-do/services-and-support/failure-analysis-and-repair)    - [Failure Investigation](/what-we-do/services-and-support/failure-analysis-and-repair/failure-investigation)
    - [Repair Procedure Development](/what-we-do/services-and-support/failure-analysis-and-repair/repair-procedure-development)
    - [Dispute/Litigation Support](/what-we-do/services-and-support/failure-analysis-and-repair/dispute-litigation-support)
  - [Training Courses](/what-we-do/training-courses)
  - [Digital Strategy](/what-we-do/digital-strategy)  - [Automation](/what-we-do/digital-strategy/automation)
  - [Connectivity](/what-we-do/digital-strategy/connectivity)
  - [Data Science](/what-we-do/digital-strategy/data-science)
  - [Modelling and Simulation](/what-we-do/digital-strategy/modelling-and-simulation)
  - [Software Development](/what-we-do/digital-strategy/software-development)
  - [Trending Topics](/what-we-do/trending-topics)
  - [Our Processes](/what-we-do/our-processes)
  - [A to Z](/what-we-do/a-z)
  - [FAQs](/technical-knowledge/faqs)
- [Media and events](/media-and-events)  - [Events Diary](/media-and-events/events-diary/all-events)
  - [Press Releases](/media-and-events/press-releases)
  - [Insights](/media-and-events/insights)
  - [Our Stories](/media-and-events/our-stories)
  - [Our Podcast](/media-and-events/science-and-engineering-podcasts)
- [Technical knowledge](/technical-knowledge)  - Search
- [Careers](/careers)  - [Current Vacancies](/careers/current-vacancies)
  - [Career Options](/careers/career-options)  - [Administrative and Customer Services](/careers/career-options/administrative-and-customer-services)
  - [Apprenticeships](/careers/career-options/apprenticeships)
  - [Corporate and Business Support](/careers/career-options/corporate-and-business-support)
  - [Engineering Technicians](/careers/career-options/engineering-technicians)
  - [Engineering, Researchers and Scientists](/careers/career-options/engineering-researchers-and-scientists)
  - [Internships and Industrial Placements](/careers/career-options/internships-and-industrial-placements)
  - [Marketing and Business Development](/careers/career-options/marketing-and-business-development)
  - [Postgraduate](/careers/career-options/postgraduate)
  - [Training and Examinations](/careers/career-options/training-and-examinations)
  - [Life at TWI](/careers/life-at-twi)  - [Benefits](/careers/life-at-twi/benefits)
  - [Our People](/careers/our-people)
- [Engineering Jobs](/theweldinginstitute-jobs)
- [Contact us](/contact)  - [Find Us](/contact/find-us)
  - [TWI Addresses](/contact/twi-addresses)

- [Facebook](http://www.facebook.com/twiltd)
- [Twitter](https://twitter.com/twi_ltd)
- [LinkedIn](http://www.linkedin.com/groups?mostPopular=&gid=2888580)
- [YouTube](http://www.youtube.com/twiltd)
- [Instagram](https://www.instagram.com/twi_ltd/)

- [Home](/)
- [Technical Knowledge](/technical-knowledge)
- [FAQs](/technical-knowledge/faqs)
- What is Annealing?

# What is Annealing? A Complete Process Guide

[Contact Us](mailto:contactus@twi.co.uk)

- [Facebook](https://www.facebook.com/TwiLtd/)
- [Twitter](https://twitter.com/twi_ltd)
- [LinkedIn](https://www.linkedin.com/company/14139/)
- [YouTube](https://www.youtube.com/channel/UCVyzolRz8436963AmklQM4Q)
- [Instagram](https://www.instagram.com/twi_ltd/)

Annealing is a heat treatment process that changes the physical and sometimes also the chemical properties of a material to increase ductility and reduce the hardness to make it more workable.

The annealing process requires the material above its recrystallization temperature for a set amount of time before cooling. The cooling rate depends upon the types of metals being annealed. For example, ferrous metals such as steel are usually left to cool down to room temperature in still air while copper, silver and brass can either be slowly cooled in air or quickly quenched in water.

The heating process cause atoms to migrate in the crystal lattice and the number of dislocations reduces, which leads to the change in ductility and hardness. The heat treated material recrystallizes as it cools. The crystal grain size and phase composition depend on the heating and cooling rates and these, in turn, determine the material properties.

Hot or cold working of the pieces of metal following annealing alters the material structure once more, so further heat treatments may be required to attain the desired properties.

However, with knowledge of material composition and phase diagram, heat treating can soften metals and prepare them for further working such as forming, shaping and stamping, as well as preventing brittle failure.

## How does an Annealing Furnace Work?

An annealing furnace works by heating a material above the recrystallization temperature and then cooling the material once it has been held at the desired temperature for a suitable length of time. The material recrystallizes as it cools once the heating process has caused atom movement to redistribute and eradicate dislocations in the workpiece.

Annealing works in **three stages** – the recovery stage, recrystallization stage and the grain growth stage. These work as follows:

### 1\. Recovery Stage

This stage is where the furnace or other heating device is used to raise the temperature of the material to such a point that the internal stresses are relieved.

### 2\. Recrystallization Stage

Heating the material above its recrystallization temperature but below its melting point causes new grains to form without any residual stresses.

### 3\. Grain Growth Stage

Cooling the material at a specific rate causes new grains to develop. After which the material will be more workable. Subsequent operations to alter mechanical properties can be carried out following annealing.

## When is Annealing Required and Why is it Important?

Annealing is used to reverse the effects of work hardening, which can occur during processes such as bending, cold forming or drawing. If the material becomes too hard it can make working impossible or result in cracking.

By heating the material above the recrystallization temperature, it is made more ductile and therefore ready to be worked once more. Annealing also removes stresses that can occur when welds solidify. Hot rolled steel is also shaped and formed by heating it above the recrystallization temperature. While steel and alloy steel annealing is common, other metals can also benefit from the process, such as aluminium, brass, and copper.

Metal fabricators use annealing to help create complex parts, keeping the material workable by returning them close to their pre-worked state. The process is important in maintaining ductility and reducing hardness after cold working. In addition, some metals are annealed to increase their electrical conductivity.

## Can Annealing be Used with Alloys?

Annealing can be carried out with alloys, with a partial or full anneal being the only methods used for non-heat treatable alloys. The exception to this is with the 5000 series alloys, which can be given low temperature stabillisation treatments.

Alloys are annealed at temperatures of between 300-410°C, depending on the alloy, with heating times ranging from 0.5 to 3 hours, depending on the size of the workpiece and the type of alloy. Alloys need to be cooled at a maximum rate of 20°C per hour until the temperature is reduced to 290°C, after which the cooling rate is not important.

## Advantages

The main advantages of annealing are in how the process improves the workability of a material, increasing toughness, reducing hardness and increasing the ductility and machinability of a metal.

The heating and cooling process also reduces the brittleness of metals while enhancing their magnetic properties and electrical conductivity.

## Disadvantages

The main drawback with annealing is that it can be a time consuming procedure, depending on which materials are being annealed. Materials with high temperature requirements can take a long time to cool sufficiently, especially if they are being left to cool naturally inside an annealing furnace.

## Applications

Annealing is used across a variety of industries where metals need to be worked into complex structures or worked on several times.

## Who Discovered Annealing?

Annealing dates back hundreds of years, as evidenced by the word itself, which comes from the Middle English ‘anelen,’ meaning to set on fire or kindle, as well as bake and temper.

Middle English was spoken and written in England from 1150 until 1500 and is a descendant of Old English.The term had spelling variations, such as the Middle English ‘onǣlan,’ and was used as in this instruction from 1400, ‘Take þe plates of bras pannes or of cawdrouns and anele hem in þe fire rede hoot’ (“Take the plates of brass pans or of cauldrons and anneal them in the fire red hot”).

While we do not know exactly who discovered annealing, the etymology shows that it was in practice at least 900 years ago.

[**Heat Treatment Services** \
\
TWI have installed a new heat treatment facility to support both our internal projects and to support our members.](/what-we-do/services-and-support/manufacturing-production-support/heat-treatment)

[**Services and Support** \
\
We can help you at every stage of the design, creation, operation and decommissioning of your products or assets – through effective understanding and application of welding, joining, inspection and allied technologies.](/what-we-do/services-and-support)

For more information please email:

[contactus@twi.co.uk](mailto:contactus@twi.co.uk)

#### TWI Ltd (Head Office)

Granta Park, Great Abington, Cambridge, CB21 6AL, UK

+44(0)1223 899000

[contactus@twi.co.uk](mailto:contactus@twi.co.uk)

[Subscribe to our newsletters](/account/newsletter-preferences?s=footerlink "Subscribe to our newsletters")

- [Facebook](https://www.facebook.com/TwiLtd/)
- [Twitter](https://twitter.com/twi_ltd)
- [LinkedIn](https://www.linkedin.com/company/twi)
- [YouTube](https://www.youtube.com/channel/UCVyzolRz8436963AmklQM4Q)
- [Instagram](https://www.instagram.com/twi_ltd/)

![ROSPA 2024](/site-elements/images/rospa-2024-gold-award.png)

Copyright © 2024 TWI Ltd. All rights reserved.

[Terms](/terms) [Privacy](/privacy) [Cookies](/cookies)

#### Group Companies

- [The Welding Institute](https://theweldinginstitute.com)
- [Engineering Jobsite](https://twi-global.com/theweldinginstitute-jobs)
- [Training and Examinations](https://www.twitraining.com/)
- [TWI Certification](https://www.twicertification.com/)
- [CSWIP](https://www.cswip.com/)
- [TWI Software](https://www.twisoftware.com/)

- [The Test House](http://www.thetesthouse.co.uk/)
- [NSIRC](https://twi-global.com/nsirc/)
- [TWI Innovation Network](https://twi-global.com/innovation-network/)

Copyright © 2024 TWI Ltd. All rights reserved. [Terms](/terms) [Privacy](/privacy) [Cookies](/cookies)