What is the past tense and participle of steel?

The verb "steel" is not a regular verb, and it doesn't have a simple past tense or participle form. It's a transitive verb that means "to make strong or firm" or "to make into steel."

Here's how you would express the past tense and participle of "steel":

* Past Tense: You would typically use the phrasal verb "steeled oneself" to express the past tense. For example, "He steeled himself against the cold."

* Participle: The past participle of "steel" is also typically used in a phrasal verb like "be steeled." For example, "He was steeled by his belief in justice."

Examples:

* Present Tense: The blacksmith steels the blade.

* Past Tense: He steeled himself against the fear.

* Participle: They were steeled for the challenge ahead.

If you're looking to use "steel" in the past tense or participle in a different context, please provide more information so I can assist you.