02 Oct HARDENING STEEL
During my apprenticeship as an engineer, one day a week was spent at the technical college to learn the theory of engineering and obtain the certificates required for a successful career in the industry.
A good lecturer can hold students attention by making the subject interesting in a graphic way. Mr Woodham taught us engineering science and he had an excellent approach to the subject.
On hardening carbon steel, he explained the process of heating the steel to about nine hundred degrees centigrade, then quenching it in non inflammable oil, usually whale oil, to harden the steel for the manufacture of cutting tools etcetera. The class would be beginning to glaze over at this point then he would say in a loud and aggressive tone “HOWEVER!!” Now alert the class took notice as he broke away from traditional teaching.
“How do you think that the Ancient Romans discovered that method? Well when they were making weapons, like their famous short swords, they quickly discovered that quenching them in water produced very hard but also very brittle blades. These often snapped on impact leaving the hapless Roman soldier holding nothing but the handle. So the blacksmiths of the day tried different methods of dousing the blades in a thicker and warmer liquid. The most successful of which turned out to be oil. In Roman times the only oils available were vegetable oils, very precious and very expensive to produce.
HOWEVER!! An alternative liquid was FRESH BLOOD! Already at the right temperature and consistency and as they had many slaves, which were ten a penny, the following method became common practice. The swords were heated to the required temperature, just imagine the screaming slave being brought in and forced to kneel in front of the forge. With one sweeping blow from a huge axe , his or her head would be lopped from their body and the red hot swords plunged into the open neck wound until brought down to the required temperature.”
I for one never forgot that description and Mr Woodham’s exciting and melodramatic lectures.
Come the end of the academic year and the City and Guilds examinations, we students strived to produce the standards required to pass up to the next stage of our education.
“Answer the questions as concisely as you can” we were told,
“But if you can add any information to verify your answer and show the examiner that you fully understand the subject, it may well gain you extra marks”
We all sat down for the “Engineering Science” paper. I was delighted to see question one.
‘Describe the procedure for hardening carbon steel and give your reasons for the method used.’
I described the entire procedure and the reasons for using oil for quenching, producing larger grain growth in the hardened metal and although hard, less brittle than if using water.
Eager to show how much I knew about the process I added
“HOWEVER, how do you think the Ancient Romans discovered……………..”
499 words Michael White 2019