Well, Niagara says this about their product:

FACT: THE GRADE 1144 MODIFIED Grade AISI 1144 was originated by the LaSalle Steel Company in the mid-1930's for the purpose of making STRESSPROOF.

FACT: THE PATENT The original patent for STRESSPROOF, "the steel product and method of manufacture", was based on cold drawing with heavy drafts, i.e., higher-than-normal drafts. This was followed by the highest temperature stress relieving treatment possible to obtain a combination of properties… strength, wear resistance, minimum warpage, and excellent machinability.

FACT: HIGH TEMPERATURE STRESS RELIEVING The importance of high temperature stress relieving to obtain maximum ductility, minimum warpage and excellent machinability is a major part of the original patent. The stress relieving temperature selection is based on 60 years of experience and thorough documentation.

FACT: PATENTED DRAWING DIES Niagara LaSalle's patented drawing dies have always been the most critical part of producing STRESSPROOF. Therefore, a warpage test is always performed on the first bar drawn through either a new or reground die. Warpage tests are also regularly made as part of a standard quality assurance procedure. Niagara LaSalle is the only mill to use a warpage test. The results then become an integral part of the quality assurance program.

FACT: SURFACE QUALITY To assure surface quality, comparitor or roto bar testing for seams on every order is a part of the STRESSPROOF manufacturing process. To further improve quality, Niagara LaSalle reduced the standard seam depth tolerance for STRESSPROOF from 0.0015 per each 1/16" to 0.0010 per each 1/16". This can mean a savings of 3% in material weight purchased.

FACT: MACHINABILITY ASSURANCE Machinability testing of all STRESSPROOF is regularly done as a part of the Niagara LaSalle Quality Assurance Program. Niagara LaSalle is the only mill in the world to use a machining test as part of a production and quality assurance program.

FACT: ASTM A311 SPECIFICATION This specification was written in an attempt to cover STRESSPROOF properties. This specification is very broad in that it covers eight grades and four conditions of stress relieved cold drawn bars to meet minimum mechanical property requirements.

FACT: MECHANICAL PROPERTY TESTING Mechanical property (tension) testing at Niagara LaSalle uses the largest sampling plan in the industry. A minimum of one test (tensile, yield, elongation, R/A) is made for every 50,000 lbs. or less. Mechanical property testing is always the final production operation after all processing is completed.

And I have learned something today about drill rod. It's an American term and I never quite knew what it was.