The Metallurgical Laboratory Capabilities

Tensile Testing Sheet or Tube

Full Section or any sub-sized Milled Specimen
.01% Offset Yield Strength
.02% Offset Yield Strength
.05% EUL Yield Strength
Ultimate Tensile Strength
% Total Elongation
% Uniform Elongation
%Yield Point Elongation
n-Value and K constant
r-Value
Elastic Modulus
Peak Load

The characteristics of the stress-strain curve provide a substantial amount of information regarding the steelís capability of meeting final fabrication needs, the stress at which the material will exhibit permanent deformation, the maximum stress permitted before the onset of necking, how much the material will uniformly deform, total ductility, how well the material will stretch and itís resistance to thinning.  All of these are key components that must be understood when designing parts and applying steel grades.

Hardness Testing

HRA
HRB
HRC
30T
Microhardness Testing Ė Vickers 

The microhardness test is indispensable to metallographic research when needing to measure the hardness/strength on a microscopic scale, such as welds and processed surface layers

Chemistry

Optical Emission Spectrometry
C, Mn, P, S, Si, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, B, N, Ca, Ce, La, Fe
Wet Lab Ė Chemical Etching, Preece Testing 

The ability to routinely test the chemical composition of the steel being applied to a given application is invaluable to a processor/fabricator/end user.  LJT regularly inspects in-coming coils to verify conformance from our suppliers (both chemistry and mechanical properties).  As needs arise, we can also quickly determine that appropriate coils are presented at the mill for processing and that our customers have received product produced from the appropriate steel grade.

Microscopic Examination

Microstructural Evaluations
Steel Cleanliness Ratings
Grain Size
Morphology
Decarburization
Coating thickness and microstructure
ERW Weld Quality Evaluation
Heat Affected Zone
Edge Presentation
Flowline angle determination
Bondline rating

Steel properties highly depend on its structures. The internal structures determine how the steel performs under a given application. The effects of most industrial processes applied to steel to control their properties can be explained by studying their rnicrostructures.  Sub-par microstructural characteristics can lead to weld defects that may result in service failures.  Close examination of both the weld and parent metal are essential in documenting potential causes which can then help to develop solutions to prevent the occurrence in the future.

Macroscopic Examination

Destructive Testing: Flare, Flattening, Crush testing
Surface topography evaluation
Roughness profilometry 

The ability to simulate the fabrication processes our product undergoes is invaluable in assessing capabilities and conformance.  At Lock Joint Tube, the ability to conduct flare, wall-to-wall flattening and crush testing greatly aids in characterizing overall quality of the product.  For those applications also requiring paint-quality surface finishes, roughness profilometry allows us to measure the texture of the surface in terms of average roughness and peak count in order to determine conformance to customer expectations.

Failure Analyses / Fracture Investigations

The failure analyses conducted focus on the metallurgical aspects of the observed field/service failure.  Failure analysis consists of investigations to find out how and why something failed. Understanding the actual reason for failures is absolutely required to avoid recurrence and prevent failure in similar equipment. The analysis should also help with the understanding and improvement of design, materials selection, fabrication techniques, and inspection methods. The process starts with a review of background information on part history (performance and properties), with the ensuing investigation dependent on the specific type of observed failure, but generally will include the following:  visual examination, macroscopic and microscopic analyses, chemical analysis, mechanical properties determination and destructive testing.

Salt Spray Testing

As more customers are demanding improved corrosion resistance, the ability to evaluate and understand how steel tubing produced from coated sheet steels will perform in the field becomes very important.  Lock Joint Tube is working to develop this expertise in order to provide our customers with the knowledge and comfort that our products will meet their demanding requirements.