09212017Thu
Last updateThu, 21 Sep 2017 5pm

i

Subscribe SUM17

FREE SUBSCRIPTION*

•  Print magazine
•  Digital magazine
•  VALVE eNews
Read the latest issue

*to qualified valve professionals in the U.S./Canada

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

Advertisement
i

Industry Headlines

Velan Announces New Sales Structure

6 HOURS AGO

Velan is re-designing its sales structure to be better aligned with customers’ market approach. This change is intended to focus Velan’s resources on maximizing impact and competitiveness in today’s challenging economy.

Paul Dion has been appointed as vice-president of sales, process ...

Readmore

MSS Revises Standards for Instrument Valves, Sealing of Rising Stem Valves

2 DAYS AGO

The Manufacturers Standardization Society (MSS) is pleased to announce the publication of the following revised Standard Practices:

  • MSS SP-99-2016a, Instrument Valves (replaces 2016 edition)
  • MSS SP-105-2016a, Instrument Valves for Code Applications (replaces 2016 edition)
  • MSS SP-120-2017, Flexible Grap...

Readmore

Construction Underway on Atlantic Sunrise Pipeline

1 DAY AGO

Construction is officially underway in Pennsylvania on the greenfield portion of the Atlantic Sunrise pipeline project – an expansion of the existing Transco natural gas pipeline to connect Marcellus gas supplies with markets in the Mid-Atlantic and Southeastern U.S.

Construction broke ground in ...

Readmore

EIA Projects 28% Increase in World Energy Use by 2040

1 DAY AGO

The U.S. Energy Information Administration (EIA) projects that world energy consumption will grow by 28% between 2015 and 2040. Most of this growth is expected to come from countries that are not in the Organization for Economic Cooperation and Development (OECD), and especially in countries where d...

Readmore

U.S. Manufacturers Seeking More Renewable Energy

9 HOURS AGO

A new report from David Gardiner and Associates finds that 83% of the largest manufacturing companies with a U.S. footprint have established greenhouse gas reduction targets and 25% of manufacturers have established renewable energy targets. The analysis also finds that enabling access to renewable en...

Readmore

Harvey Caused Steep Drop in U.S. Industrial Output

3 DAYS AGO

Industrial production declined 0.9% in August following six consecutive monthly gains. Hurricane Harvey is estimated to have reduced the rate of change in total output by roughly 0.75%. The index for manufacturing decreased 0.3%; storm-related effects appear to have reduced the rate of change in facto...

Readmore

NACE MR0103 and Duplex Stainless Steels

materials_q_and_a_graphicQ: Why are some suppliers reluctant to produce duplex stainless-steel valves that are compliant with NACE MR0103?

 

A: Duplex stainless steels are those that are chemically balanced to provide a target microstructure of 50% austenite phase and 50% ferrite phase. Duplex stainless-steel valves required to meet NACE MR0103 will almost always be installed in a sour, corrosive, chloride-containing environment, so it is essential the material provides optimized resistance to sulfide stress cracking, chloride stress corrosion cracking, chloride pitting and general corrosion.

 

The task group that created the NACE MR0103 document, “Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments,” recognized that microstructure is a key factor influencing the properties of duplex stainless steel. They also recognized that the microstructure is influenced strongly by chemistry and by heating and cooling during processing of the material. As a result, NACE MR0103 includes some very stringent requirements for duplex stainless steels, especially with regard to welding. Since most valve bodies (and many bonnets) are produced from castings, welding will be performed. Although most welding will be minor and cosmetic in nature, NACE MR0103 does not distinguish between minor and major weld repairs when it comes to welding requirements for these materials.

During welding, the cooling rates that occur in the weld deposit and in the heat-affected zone (HAZ) can have dramatic effects on the final microstructure. Higher cooling rates tend to promote higher ferrite levels, which are advantageous for chloride stress corrosion cracking resistance but detrimental to sulfide stress cracking resistance and impact resistance. Conversely, slower cooling rates promote lower ferrite levels, which will result in increased sulfide stress cracking resistance and toughness, but reduced chloride stress corrosion cracking resistance, and can allow the formation of harmful second phases that detract from the overall corrosion resistance of the material.

Therefore, successful welding of duplex stainless steels to provide optimum properties is a fine balancing act, which requires careful control of welding parameters that affect the cooling rate of the weldment.

Welding Requirements

In order to achieve the necessary control over cooling rates during welding, NACE MR0103 includes several requirements with regard to qualification of welding procedures:

  1. Each procedure qualification specimen must be hardness surveyed using to 10 kg Vickers hardness scale. The readings must average no more that 310 HV 10, and no individual reading is allowed to exceed 320 HV 10.
  2. The ferrite content must be measured metallographically in the weld deposit and HAZ of each procedure qualification specimen. The measured ferrite content must fall within the 35% to 65% range in all measured locations.
  3. The heat input required per the resulting welding procedure specification must not deviate by more than 10% from the heat input used when producing the procedure qualification specimen(s).
  4. The base metal thickness range qualified by a given procedure specimen of thickness T is 0.8T to 1.2T.

 

Requirements 1 and 2, although they add testing over and above the normal ASME Section IX requirements, are not overly problematic.

  • Latest Post

  • Popular

  • Links

  • Events

Advertisement

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association