The C.E.R.T System
When your requirements call for constant extension rate or slow strain rate testing, Cortest offers a range of products that can form a total capability. Systems components include load frames, environmental chambers, controls, and ancillary equipment. These apparatuses permit testing to simulate a broad range of load, temperature, pressure, strain rate and environmental conditions using both mechanical and electrochemical corrosion testing techniques.

Cortest has been successful for more than 20 years in the design and manufacture of load frames for SSRT, Constant Extension Rate Tester (CERT) and Corrosion Fatigue (CF) Computer-Aided Test (CAT) Systems.

Computerized Virtual Instrument
Virtual Instrument and Constant Extension Rate Tester (V I - CERT)
An alliance has been formed between National Instruments and Cortest to bring state-of-the-art corrosion test capabilities to laboratories worldwide.

Cortest and National Instruments V I for SSRT/CERT is made powerful and simple with the newest LabVIEW 6.1 for Windows 98/NT.

The newest National Instruments innovations have been integrated into Cortest V I CERT Closed Loop Feedback software controlled Load Frame and Autoclave Test Systems.

The Cortest/NI-PXI Programmable Computerized Instrument Interface comes configured with internal Stepper Motor Drive Controller, Signal Conditioner for Load Cell/LVDT and Autoclave Temperature Control/Monitor System.

With this V I CERT innovation Cortest is proud to maintain its position in the forefront of corrosion testing equipment manufacture and technology transfer.

Load Frames
Cortest's Constant Extension Rate Test (CERT) Load Frames offer accuracy and flexibility in testing the effects of slow strain rate. Offered in floor and bench models, the CERT's provide up to 10,000 psi (50 KN) load capacity with linear extension rates ranging from 10^-5 in/sec to 10^-8 in/sec. Manufactured to assure maximum accuracy in test results, the apparatus is comprised of a heavy duty load frame which minimizes system compliance while maintaining precise axial alignment of the load train, an all-gear drive system to provide consistent extension rates, and load train components of 17-4 pH steel for long service life. In the floor model design, the CERT provides maximum flexibility and working space for test sample configuration, environmental chamber design, and accessibility. The bench model is a self-contained unit mounted in a portable cart that is advantageous when space limitations are a consideration. This unit contains a convenient work area and shelf. Added features included in both models for ease of operation include quick-release pins in load train components to permit expedient vessel changeover and handwheel to apply a pre-load prior to operation.

Constant Extension Rate Test Load Frames are compatible with all Cortest vessels, control instrumentation, and ancillary equipment to create a complete test system capability.

Motion Control
Introduction
The motion control products delivered by Cortest Inc. provide high-performance, accurate motion for all motor applications. The easy-to-use software and motion controller deliver the functionality and power needed by end-users.

Motion and Measurements
The motion control has been configured to simplify the measurements and to offer the association of motion and measurements. Through the advanced software and hardware features, the system can perform specific motion operations and take measurements simultaneously.

Motion Controller and Universal Motion Interface
The motion controller offers a general-purpose controller at a lower cost. It consists of a multi-axis stepper controller, which features point-to-point motion and coordinated control. Feedback signals provide closed-loop control of position and velocity for additional accuracy.

Motor
For applications that need high positioning accuracy and repeatability, stepper motors are recommended. Also, the use of stepper motors with a microstepping drive gives additional accuracy for smooth and low-vibration applications.

• Stepper Motor
  The operating procedure of stepper motor is based on the principles of commutation or alternating magnetic forces to provide accurate controlled motion. The drive currents and voltages in motor coil windings sequence the torque and, consequently, the motion. In a stepper motor, the motor moves by small discrete steps.
• Microstepping in Stepper Motor Systems
  The Cortest stepper motor driver component provides additional resolution by offering microstepping. Each full step is subdivided into microsteps. Microstepping is based on the proportioning of currents in each coil, which results in precisely balanced electromagnetic forces for accurate positioning between the full steps. With microstepping, the number of steps per revolution is multiplied and the motion resolution

Stepper Motor Power Drive
The stepper motor power drive provides reliable and easy-to-connect solutions for motion controller. This unit meets the requirements for motion drive and motion I/O, control, and feedback signals. It offers a powered motor driver with the features of a Universal Motion Interface (UMI).

Modular Instrumentation and Distributed I/O
The PXI modular instrumentation consists of a modular industrial packaging associated with a PC technology (Microsoft Windows compatible), which provide the optimum solutions for measurements. The computer-based measurement and automation are performed in the most effective way by using standardized timing and triggering.

The modular distributed I/O system appears in a modular architecture delivered in a rugged and reliable package. The distributed I/O systems can be used for analog and digital I/O with networking options and are available from 8 to 16 channels. The easy-distributed systems represent cost-saving solutions and improve the reliability.

Motion Control Software and Front Panel User Interface
The Labview software offers a very friendly though very productive user interface for complete control and measurement of a test system. Based on a graphical programming language, the user interface can easily be modified by our developer to include the features requested by the end-user. The Cortest user interface shows excellent features for test and development programs as well as for process monitoring, research and analysis programs. A range of data acquisition and instrumentation systems is available.

The front panel user interface from Cortest Inc. is a simple and appropriate environment for the motion control of stress corrosion cracking and corrosion fatigue tests.

Because of the faster development and optimal performance of the Labview software, it represents the best investment. The open development environment allows our engineers to include the available hardware libraries for data acquisition, signal conditioning, computer-based instruments and motion control. The optimal system can therefore be easily configured to customized systems

Additional Controls
Controlling and monitoring test conditions are reliably and accurately accomplished with Cortest instrumentation. Designed as integral components of the CERT system, controls are available in either individual modules or combination units to completely meet instrumentation needs.

In addition to the units that control and monitor physical mechanical test conditions, Cortest also provides free-standing electrochemical instrumentation at the customer request. It offers increased capability and precision with the standard Cortest instrumentation packages.

Cortest's High Temperature External Reference Electrode works in conjunction with our vessel and instrumentation technology to permit electrochemical testing in high temperature hostile environments. Designed for applications in which the entire electrode does not need to be located within a high temperature zone, this electrode will work in temperatures ranging from 25°C to 220°C.

Environmental Chambers
Environmental Chambers designed for test conditions ranging from ambient temperature and pressure to in excess of 2,000 psi at 220°C, are manufactured by Cortest for use with its CERT Systems.

The unique TemPressure vessel provides the user with a pull-through sliding seal, which permits the testing of the effects of strain rate on specimens in environmental conditions similar to those encountered in actual field situations. Standard vessels are manufactured from 316 Stainless Steel, Hastelloy C-276, or Titanium alloys to withstand a wide range of severe corrosion environments. Units can be operated to 2,000 psi at 220°C. A metal seal ring is combined with a bolted closure for operating safely. Provided with the vessel is a control panel, connected to the chamber with Hastelloy tubing to allow the introduction and purging of test gases. A pressure gauge is also included. Temperature is applied through external electrical resistance heaters and controlled with standard Cortest instrumentation.

When test requirements call for the evaluation of specimens in a compact tension or DCB configuration, the Cortest Fatigue Test Cell will meet your needs. The cell is specifically configured to house fracture mechanics-type specimens. Designed to be placed horizontally within the load frame, the fatigue cell both provides maximum space for the specimen and permits easy access for monitoring corrosion effects. Standard operating pressures and temperatures are 2,000 psi at 220°C. Materials of construction, control panel design, vessel heating, and monitoring are the same as provided with the TemPressure Vessel.

If operating temperatures higher than our standard range are required, optional water-cooled grip and seal configurations are available for testing to 500°C and 5,000 psi on both the TemPressure and Fatigue Test Cells.

For use in less severe applications, Cortest also offers glass vessels for ambient conditions, a high temperature vessel for use up to 100°C, and vessels of Teflon construction for special environmental conditions. Vessel porting required for electrochemical testing is available on all environmental chambers.