Carbon & Alloy Steel

1018 ALLOY STEEL

This low carbon steel has good case hardening properties. Although not classed as a screw machine steel, at times it may be specified. This is an excellent steel for bending and cold forming, with good brazing and welding properties.

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1045 ALLOY STEEL

This medium carbon steel is used for heat treating (quenching and tempering). Although it has only a fair response to conventional quenching, it is widely used where requirements are not too stringent. It is also used extensively in induction hardening applications. This is not normally considered a screw machine steel and is only fair for brazing and welding. However, it can be forged satisfactorily and is the most common shafting steel in the medium carbon range.

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1215 CARBON STEEL

1215 has essentially eliminated a number of similar free machining grades, such as 1212. Both 1215 and 1213 machine considerably faster than 1212 and provide good surface finish and brazing properties. These steels are difficult to weld and are not recommended for case hardening. They are generally used where mechanical properties can be sacrificed for machinability.

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12L14 CARBON STEEL

A free machining, resulphurized, lead-bearing steel for high volume production parts. Used for parts where considerable machining is required. With good ductility, this grade can be used for parts involving bending, crimping, or riveting.

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4140 ALLOY STEEL

This alloy responds well to heat treatment. Its chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength. In the annealed condition it machines at 110 sfm. Other desirable properties include good wear resistance, excellent toughness and good ductility in the quenched and tempered condition.

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8620 ALLOY STEEL

The most widely used carburizing alloy. Its nickel content imparts good toughness and ductility. The chromium and molybdenum increases hardness penetration and wear-ability. This steel's well balanced alloy content permits hardening to produce a strong, tough core and high case hardness. It machines at 110 sfm and has good welding qualities.

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E.T.D. 150®

A high strength material made by Niagara LaSalle's patented "e.t.d."® (elevated temperature drawing) process. Eliminates heat treating and secondary operations such as straightening, finish grinding, cleaning, and inspections. "e.t.d." 150® can be roll threaded, knurled and plated. Suitable for induction hardening. "e.t.d." 150® is also electro-magnetically tested using induced eddy currents.

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STRESSPROOF®

STRESSPROOF® is made by a patented process which consists of drawing the bar through a special die under heavy draft, then stress relieving it in a precisely controlled furnace. STRESSPROOF® offers improved wearability without case hardening, strength without heat treating, plus excellent machinability and tool life. STRESSPROOF® is electro-magnetically tested using eddy currents. Other benefits include resistance to fatigue and stress, balanced working and minimum warpage and distortion.

STRESSPROOF® can also be induction hardened, but should be watched for quench cracks.

100,000 psi minimum yield strength. Strength without heat treating. Guaranteed machinability, minimum warpage. Elimination of heat treating means energy savings and reduced processing costs.

Stressproof Difference: The Only Steel Bar Pretested for Machinability

Consistent quality is becoming increasingly important to steel users over a wide range of products. This is particularly true in the case of the uniformity of machinability of cold finished steel bars, because of the ever greater automation in the machine shop. The present new generation of computer-controlled machine tools is less tolerant of differences in tool life, emphasizing the need for materials that are dependable performers.

Niagara LaSalle has recognized this need for product uniformity, since it has worked in the field of machining for many years in close contact with production machine shops. Through the years, the desirability of having available a quick and inexpensive machinability test that could be used as a routine quality control check was often discussed. Finally, several years ago, after much painstaking research, Niagara LaSalle did develop a new machinability test ideally suited for quality control purposes and the monitoring of certain specialty products where uniform machinability is important.

Niagara LaSalle's machining test is different from most other tests now in use in that it is basically a "go/no-go" test, which is an integral part of the machining cycle used to prepare the standard tension test specimen needed for releasing every lot of STRESSPROOF® produced. When this machining procedure is done with a modern computer-controlled lathe, the test is simple, accurate, and inexpensive to carry out.

It is recognized that this test will not pick up every conceivable problem associated with machining, particularly those related to residual stresses or surface problems. However, the test is very sensitive to effects associated with the basic nature of the steel, such as tensile properties, hardness, metallographic differences in structure and inclusions, and variations in chemical composition.

It is strongly felt that in our modern computer age, uniformity in machinability of a product has become a key factor in improved productivity, and Niagara LaSalle will continue to be responsive to the needs of its customers.

STRESSPROOF not only meets the minimum properties of ASTM A311, but it also has controlled low stresses, reliable machining, and improved surface quality. Result is longer part life with less manufacturing costs.

Comparison of ASTMA 311 and STRESSPROOF®

FACTS

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.

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