<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31410348</termId><termName>case-hardening</termName><termType>PT</termType><termNote><![CDATA[ Producing a hard surface layer on steel, as by carbonizing, cyaniding, and flame hardening. ]]></termNote><termCreatedDate>2026-03-30 20:50:20</termCreatedDate><relation><relationType>UF</relationType><termId>31410349</termId><termName>case hardening</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31410350</termId><termName>case-hardened</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31371890</termId><termName>surface hardening</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31317829</termId><termName>case hardening</termName><termType>PT</termType></relation></term>  </Zthes>