A metal processing system, comprising: a dimensionally variable heat treatment apparatus having an opening for accepting a metal article moving in a processing direction, the heat treatment apparatus including: one or more heating units positionable proximate the metal article on a first side of a separation plane intersecting the metal article to raise a temperature of a first portion of the metal article on the first side of the separation plane at or above a heat treatment temperature; and one or more cooling units positionable proximate the metal article on a second side of the separation plane to maintain a second portion of the metal article on the second side of the separation plane below the heat treatment temperature, wherein the metal article is moving in the processing direction, and wherein the dimensionally variable heat treatment apparatus is a width-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and a lateral axis of the metal article, or wherein the dimensionally variable heat treatment apparatus is a thickness-variable heat treatment apparatus, wherein the separation plane is parallel to a top or bottom surface of the metal article, or wherein the dimensionally variable heat treatment apparatus is a length-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and parallel a lateral axis of the metalarticle. one or more heating units positionable proximate the metal article on a first side of a separation plane intersecting the metal article to raise a temperature of a first portion of the metal article on the first side of the separation plane at or above a heat treatment temperature; and one or more cooling units positionable proximate the metal article on a second side of the separation plane to maintain a second portion of the metal article on the second side of the separation plane below the heat treatment temperature, wherein the metal article is moving in the processing direction, and wherein the dimensionally variable heat treatment apparatus is a width-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and a lateral axis of the metal article, or wherein the dimensionally variable heat treatment apparatus is a thickness-variable heat treatment apparatus, wherein the separation plane is parallel to a top or bottom surface of the metal article, or wherein the dimensionally variable heat treatment apparatus is a length-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and parallel a lateral axis of the metalarticle. the dimensionally variable heat treatment apparatus is a width-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and a lateral axis of the metal article, or wherein the dimensionally variable heat treatment apparatus is a thickness-variable heat treatment apparatus, wherein the separation plane is parallel to a top or bottom surface of the metal article, or wherein the dimensionally variable heat treatment apparatus is a length-variable heat treatment apparatus, wherein the separation plane is perpendicular to a top or bottom surface of the metal article and parallel a lateral axis of the metalarticle.